解决问题模型

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Problem-Solving Models 
::解决问题模型

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We always think of mathematics as the subject in school where we solve lots of problems. Problem solving is necessary in all aspects of life. Buying a house, renting a car, or figuring out which is the better sale are just a few examples of situations where people use problem-solving techniques. In this book, you will learn different strategies and approaches to solving problems. In this section, we will introduce a problem-solving plan that will be useful throughout this book.
::我们总是认为数学是我们解决许多问题的学校的科目。 问题解决在生活的各个方面都是必要的。 买房、租车或找出哪个是更好的销售只是人们使用解决问题技术的几个例子。 在这个书中,你会学到解决问题的不同策略和方法。 在这一部分,我们将引入一个在这本书中有用的解决问题的计划。

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Read and Understand a Given Problem Situation
::阅读和理解有问题的情况

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The first step to solving a word problem is to read and understand the problem. Here are a few questions that you should be asking yourself:
::解决单词问题的第一步是阅读和理解问题。

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• What am I trying to find out?
  ::我到底想查出什么来?
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• What information have I been given?
  ::我得到什么信息了?
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• Have I ever solved a similar problem?
  ::我曾经解决过类似的问题吗?

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This is also a good time to define any variables. When you identify your knowns and unknowns , it is often useful to assign them a letter to make notation and calculations easier.
::现在也是定义任何变量的好时机。当您识别已知的和未知的时,通常需要指定一个字母给他们,让他们更容易标记和计算。

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Make a Plan to Solve the Problem
::制定解决问题的计划

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The next step in the problem-solving plan is to develop a strategy . How can the information you know assist you in figuring out the unknowns?
::解决问题计划的下一步是制定战略。您知道的信息如何帮助您了解未知因素?

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Here are some common strategies that you will learn:
::以下是一些共同的战略,你们将学习:

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• Drawing a diagram.
  ::绘制图表。
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• Making a table.
  ::做一个桌子。
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• Looking for a pattern .
  ::寻找一个模式。
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• Using guess and check .
  ::使用猜测和检查。
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• Working backwards .
  ::反向工作。
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• Using a formula .
  ::使用公式。
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• Reading and making graphs.
  ::阅读和制作图表。
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• Writing equations.
  ::写方程式
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• Using linear models.
  ::使用线性模型。
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• Using .
  ::使用。
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• Using the right type of function for the situation.
  ::使用正确的函数类型来应对情况。

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In most problems, you will use a combination of strategies. For example, looking for patterns is a good strategy for most problems, and making a table and drawing a graph are often used together. The “writing an equation” strategy is the one you will work with the most in your study of algebra.
::在多数问题中,您将使用多种策略组合。例如,寻找模式是解决大多数问题的好策略,而制作表格和绘制图表通常一起使用。 “写方程式”战略是您在代数研究中最会与您合作的战略。

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Solve the Problem and Check the Results
::解决问题并检查结果

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Once you develop a plan, you can implement it and solve the problem , carrying out all operations to arrive at the answer you are seeking.
::制定计划后,您可以实施计划并解决问题,执行所有行动以达成您所寻求的答案。

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The last step in solving any problem should always be to check and interpret the answer. Ask yourself:
::解决任何问题的最后一步始终应当是检查和解释答案。

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• Does the answer make sense?
  ::答案有道理吗?
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• If you plug the answer back into the problem, do all the numbers work out?
  ::如果你把答案塞回问题里, 所有的数字都能解决吗?
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• Can you get the same answer through another method?
  ::你能通过另一种方法得到同样的答案吗?

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Compare Alternative Approaches to Solving the Problem
::比较解决问题的替代办法

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Sometimes one specific method is best for solving a problem. Most problems, however, can be solved by using several different strategies. When you are familiar with all of the problem-solving strategies, it is up to you to choose the methods that you are most comfortable with and that make sense to you. In this book, we will often use more than one method to solve a problem, so we can demonstrate the strengths and weakness of different strategies for solving different types of problems.
::有时候,一种具体的方法是解决问题的最佳方法。然而,多数问题可以通过几种不同的战略来解决。当你熟悉所有解决问题的战略时,你应该选择你最满意的、对你有意义的方法。在这本书中,我们常常用一种以上的方法解决问题,这样我们就可以展示不同战略的长处和弱点,解决不同类型的问题。

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Whichever strategy you are using, you should always implement the problem-solving plan when you are solving word problems. Here is a summary of the problem-solving plan.
::无论你采用哪种策略,在解决字词问题时,你总是应该执行解决问题的计划。这里是解决问题计划的摘要。

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Step 1:
::第1步:

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Understand the problem
::了解问题

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Read the problem carefully. Once the problem is read, list all the components and data that are involved. This is where you will be assigning your variables.
::仔细读取问题。 问题一被读取, 请列出其中涉及的所有组件和数据。 这是您指定变量的位置 。

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Step 2:
::第2步:

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Devise a plan - Translate
::制定计划 - 翻译

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Come up with a way to solve the problem. Set up an equation , draw a diagram, make a chart or construct a table as a start to solve your problem solving plan.
::找到解决问题的方法。 设置方程式、 绘制图表、 绘制图表或构建表格, 以此开始解决问题的解决计划 。

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Step 3:
::第3步:

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Carry out the plan - Solve
::执行计划 - 解决

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This is where you solve the equation you developed in Step 2.
::这就是你解开第二步所开发的方程式的地方

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Step 4:
::第4步:

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Look - Check and Interpret
::- 检查和解释

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Check to see if you used all your information. Then look to see if the answer makes sense.
::检查是否使用了全部信息。 然后查看答案是否合理 。

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The most difficult parts of problem-solving are most often the first two steps in our problem-solving plan. You need to read the problem and make sure you understand what you are being asked. Once you understand the problem, you can devise a strategy to solve it.
::解决问题最困难的部分往往是我们解决问题计划中的头两步。 您需要阅读问题, 并确保您了解自己被问的问题。 一旦您了解问题, 您就可以制定解决问题的战略 。

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Let's apply the first two steps to the following problem. 
::让我们将前两步应用到下面的问题。

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Splitting a Check
::分割检查

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Six friends are buying pizza together and they are planning to split the check equally. After the pizza was ordered, one of the friends had to leave suddenly, before the pizza arrived. Everyone left had to pay $1 extra as a result. How much was the total bill?
::六位朋友一起购买比萨饼,他们计划平分支票。 披萨订货后,一位朋友在比萨到达前突然离开了。 剩下的每个人都不得不多付一美元。 账单总额是多少?

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Understand
::理解

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We want to find how much the pizza cost.
::我们想知道比萨饼要花多少钱

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We know that five people had to pay an extra $1 each when one of the original six friends had to leave.
::我们知道,当最初的六位朋友之一不得不离开时,五个人每人要多付一美元。

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Strategy
::战略战略战略战略 战略战略战略 战略

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We can start by making a list of possible amounts for the total bill.
::我们可以首先列出一份总法案的可能金额清单。

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We divide the amount by six and then by five. The total divided by five should equal $1 more than the total divided by six.
::我们将总额除以6,然后再除以5。 总额除以5应该等于1美元,超过总额除以6。

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Look for any patterns in the numbers that might lead you to the correct answer.
::查找数字中可能导致你找到正确答案的任何模式。

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In the rest of this section you will learn how to make a table or look for a pattern to figure out a solution for this type of problem. After you finish reading the rest of the section, you can finish solving this problem for homework.
::在本节的其余部分,您将学习如何制作表格或寻找模式来找到解决这类问题的办法。读完该部分的其余部分后,您可以完成家庭作业解决该问题。

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Develop and Use the Strategy: Make a Table
::战略的制定和使用:

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The method “Make a Table” is helpful when solving problems involving numerical relationships. When data is organized in a table, it is easier to recognize patterns and relationships between numbers. Let’s apply this strategy to the following example.
::“制表”方法有助于解决涉及数字关系的问题。 当数据在表格中排列时,更容易识别数字之间的模式和关系。 让我们在下面的例子中应用这一策略。

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Increasing in Increments 
::增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增 增

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Josie takes up jogging. On the first week she jogs for 10 minutes per day, on the second week she jogs for 12 minutes per day. Each week, she wants to increase her jogging time by 2 minutes per day. If she jogs six days each week, what will be her total jogging time on the sixth week?
::乔西上慢跑课。第一周,她每天慢跑10分钟,第二周,她每天慢跑12分钟。每星期,她想将慢跑时间增加2分钟。如果她每星期慢跑6天,她第六周的慢跑时间会是多少?

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Solution
::解决方案

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Understand
::理解

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We know in the first week Josie jogs 10 minutes per day for six days.
::我们知道第一周乔西慢跑 每天10分钟6天

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We know in the second week Josie jogs 12 minutes per day for six days.
::我们知道在第二个星期 乔西慢跑 每天12分钟6天。

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Each week, she increases her jogging time by 2 minutes per day and she jogs 6 days per week.
::她每周增加跑步时间每天2分钟,每周6天。

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We want to find her total jogging time in week six.
::我们想在第六周找到她的慢跑时间

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Strategy
::战略战略战略战略 战略战略战略 战略

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A good strategy is to list the data we have been given in a table and use the information we have been given to find new information.
::一个良好的战略是列出我们在表格中提供的数据,并利用我们得到的信息寻找新的信息。

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We are told that Josie jogs 10 minutes per day for six days in the first week and 12 minutes per day for six days in the second week. We can enter this information in a table:
::我们被告知,Josie慢跑第一周每天10分钟,为期6天,第二周每天12分钟,为期6天。

Week	Minutes per Day	Minutes per Week
1	10	60
2	12	72

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You are told that each week Josie increases her jogging time by 2 minutes per day and jogs 6 times per week. We can use this information to continue filling in the table until we get to week six.
::你被告知,乔西每周增加她的慢跑时间每天增加2分钟,每周6次。我们可以利用这些信息继续填满表格,直到我们到达第6周。

Week	Minutes per Day	Minutes per Week
1	10	60
2	12	72
3	14	84
4	16	96
5	18	108
6	20	120

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Apply strategy/solve
::应用战略/解决方案

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To get the answer we read the entry for week six.
::为了得到答案,我们读了第6周的条目。

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Answer: In week six Josie jogs a total of 120 minutes.
::答:在6周的6周中,Josie慢跑总共120分钟。

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Check
::支票支票支票支票

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Josie increases her jogging time by two minutes per day. She jogs six days per week. This means that she increases her jogging time by 12 minutes per week.
::Josie每天的慢跑时间增加了2分钟,每周的慢跑时间增加了6天,这意味着她每周的慢跑时间增加了12分钟。

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Josie starts at 60 minutes per week and she increases by 12 minutes per week for five weeks.
::乔西每周从60分钟开始,每周增加12分钟,为期5周。

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That means the total jogging time is $\begin{array}{r}60+12\times 5=120minutes\end{array}$ .
::这意味着总慢跑时间为60+12x5=120分钟。

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The answer checks out.
::答案检查出来。

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You can see that making a table helped us organize and clarify the information we were given, and helped guide us in the next steps of the problem. We solved this problem solely by making a table; in many situations, we would combine this strategy with others to get a solution.
::你可以看到,制作一张桌子有助于我们整理和澄清我们所得到的信息,并有助于指导我们解决问题的下一步。 我们仅仅通过一张桌子来解决这个问题;在许多情况下,我们将这一战略与其他战略结合起来,以找到解决办法。

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Develop and Use the Strategy: Look for a Pattern
::制定和使用战略:寻找模式

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Looking for a pattern is another strategy that you can use to solve problems. The goal is to look for items or numbers that are repeated or a series of events that repeat. The following problem can be solved by finding a pattern.
::查找一个模式是您可以用来解决问题的另一个策略。 目标是查找重复的项目或数字或一系列重复的事件。 找到一个模式可以解决以下的问题 。

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Arranging Tennis Balls 
::安排网球球

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You arrange tennis balls in triangular shapes as shown. How many balls will there be in a triangle that has 8 rows?
::您以显示的三角形安排网球。 在有 8 行的三角形中会有多少球 ?

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Solution
::解决方案

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Understand
::理解

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We know that we arrange tennis balls in triangles as shown.
::我们知道,我们安排网球 在三角形显示。

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We want to know how many balls there are in a triangle that has 8 rows.
::我们想知道在有8行的三角形中有多少球。

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Strategy
::战略战略战略战略 战略战略战略 战略

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A good strategy is to make a table and list how many balls are in triangles of different rows.
::一个很好的策略是绘制一张表格,列出不同行三角形中有多少球。

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One row: It is simple to see that a triangle with one row has only one ball.
::一行:很容易看到一行的三角形只有一个球。

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Two rows: For a triangle with two rows, we add the balls from the top row to the balls from the bottom row. It is useful to make a sketch of the separate rows in the triangle.
::两行:对于带有两行的三角形,我们从上行将球添加到下行的球中。对三角形中各行绘制草图很有用。

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Three rows: We add the balls from the top triangle to the balls from the bottom row.
::三行:我们从上三角形将球添加到下行的球中。

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Now we can fill in the first three rows of a table.
::现在我们可以填满前三排的桌子了

Number of Rows	Number of Balls
1	1
2	3
3	6

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We can see a pattern.
::我们可以看到一个模式。

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To create the next triangle, we add a new bottom row to the existing triangle.
::要创建下一个三角形, 我们在现有的三角形中添加一个新的底线行 。

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The new bottom row has the same number of balls as there are rows. (For example, a triangle with 3 rows has 3 balls in the bottom row.)
::新底行的球数与行的球数相同。 (例如,3行的三角形在底行有3个球。 )

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To get the total number of balls for the new triangle, we add the number of balls in the old triangle to the number of balls in the new bottom row.
::要获得新三角形的球总数, 我们将旧三角形中的球数加入新底线中的球数。

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Apply strategy/solve:
::应用/解决策略 :

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We can complete the table by following the pattern we discovered.
::我们可以按照我们发现的模式完成表格。

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Number of balls = number of balls in previous triangle + number of rows in the new triangle
::球数 = 前三角形中的球数 + 新三角形中的行数

Number of Rows	Number of Balls
1	1
2	3
3	6
4	$\begin{array}{r}6+4=10\end{array}$
5	$\begin{array}{r}10+5=15\end{array}$
6	$\begin{array}{r}15+6=21\end{array}$
7	$\begin{array}{r}21+7=28\end{array}$
8	$\begin{array}{r}28+8=36\end{array}$

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Answer There are 36 balls in a triangle arrangement with 8 rows.
::答案是,三角形配方有36个球,有8行。

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Check
::支票支票支票支票

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Each row of the triangle has one more ball than the previous one. In a triangle with 8 rows,
::三角形的每行有一个比前一行多的球。在有8行的三角形中,

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row 1 has 1 ball, row 2 has 2 balls, row 3 has 3 balls, row 4 has 4 balls, row 5 has 5 balls, row 6 has 6 balls, row 7 has 7 balls, row 8 has 8 balls.
::1排有1个球,2排有2个球,3排有3个球,4排有4个球,5排有5个球,6排有6个球,7排有7个球,8排有8个球。

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When we add these we get: $\begin{array}{r}1+2+3+4+5+6+7+8=36balls\end{array}$
::当我们添加这些时, 我们得到:1+2+3+3+4+5+6+6+7+8=36球

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The answer checks out.
::答案检查出来。

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Notice that in this example we made tables and drew diagrams to help us organize our information and find a pattern. Using several methods together is a very common practice and is very useful in solving word problems.
::请注意,在这个例子中,我们制作了表格和图表,以帮助我们整理信息和找到模式。 共同使用几种方法是一种非常常见的做法,对于解决文字问题非常有用。

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Example
::示例示例示例示例

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Example 1
::例1

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Casey is twice as old as Marietta, who is two years younger than Jake. If Casey is 14, how old is Jake?
::凯西比玛丽塔大两倍,比杰克小两岁 如果凯西14岁,杰克几岁?

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Let $\begin{array}{r}C\end{array}$ be the age of Casey, $\begin{array}{r}M\end{array}$ be the age of Marietta and $\begin{array}{r}J\end{array}$ be the age of Jake. We can write the following equations:
::让C是凯西的年纪,M是玛丽塔的年纪,J是杰克的年纪。我们可以写以下的方程式:

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$\begin{array}{r}C=2M\end{array}$
::C=2米

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and
::和

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$\begin{array}{r}M=J-2.\end{array}$
::M=J-2。

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We can substitute the second equation into the first, getting:
::我们可以用第二个方程式 取代第一个方程式,获得:

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$\begin{array}{r}C=2M=2(J-2)=2J-4\end{array}$ .
::C=2M=2(J-2)=2J-4。

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This gives us $\begin{array}{r}C=2J-4.\end{array}$
::这让我们有了C=2J -4

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What are possible ages for Jake that would make Casey's age 14? We can make a table based on the equation:
::Jake有什么年龄可以让Casey14岁?

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::J23456.7 8 9C024686101214

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Looking at the table, when Casey's age is 14, Jake's age is 9.
::看着桌子,当凯西14岁时,杰克9岁。

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To check the answer, evaluate the equation for $\begin{array}{r}J=9\end{array}$ :
::要检查答案, 请评估 J= 9 的方程 :

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::C=2J-4 从方程开始。 C=2( 9)-4 替代物 J=9C=18-4 简化C=14 正确!

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Review 
::回顾

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1. A sweatshirt costs $35. Find the total cost if the sales tax is 7.75%.
   ::一件运动衫需要35美元。如果销售税为7.75%,请确定总成本。
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2. This year you got a 5% raise. If your new salary is $45,000, what was your salary before the raise?
   ::如果你的新工资是45,000美元,在加薪之前你的工资是多少?
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3. Mariana deposits $500 in a savings account that pays 3% simple interest per year. How much will be in her account after three years?
   ::Mariana每年将500美元存入一个储蓄账户,每年支付3%的简单利息。 三年后她的账户将有多少?
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4. It costs $250 to carpet a room that is 14 ft by 18 ft. How much does it cost to carpet a room that is 9 ft by 10 ft?
   ::地毯费250美元,每间房间14英尺比18英尺。 地毯费多少? 9英尺比10英尺?
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5. A department store has a 15% discount for employees. Suppose an employee has a coupon worth $10 off any item and she wants to buy a $65 purse. What is the final cost of the purse if the employee discount is applied before the coupon is subtracted?
   ::百货商店对员工实行15%的折扣。 假设员工有一张折价券,每件10美元,她想买65美元的钱包。 如果在折价券扣除之前适用员工折扣,则钱包的最终成本是多少?
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6. To host a dance at a hotel you must pay $250 plus $20 per guest. How much money would you have to pay for 25 guests?
   ::要在酒店举办舞会,你必须给每个客人付250美元加20美元。
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7. Yusef’s phone plan costs $10 a month plus $0.05 per minute. If his phone bill for last month was $25.80, how many minutes did he spend on the phone?
   ::Yusef的电话计划每月花费10美元,每分钟加0.5美元。 如果他上个月的电话账单是25.80美元,他在电话上花了多少分钟?
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8. It costs $12 to get into the San Diego County Fair and $1.50 per ride.
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   1. If Rena spent $24 in total, how many rides did she go on?
      ::如果Rena总共花了24美元 她开了多少次车?
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   2. How much would she have spent in total if she had gone on five more rides?
      ::如果她再搭五趟车,她会花多少钱?
   
   ::如果Rena总共花了24美元,她又继续了多少次? 如果她又坐了5次车,她会花多少钱?
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9. An ice cream shop sells a small cone for $2.95, a medium cone for $3.50, and a large cone for $4.25. Last Saturday, the shop sold 22 small cones, 26 medium cones and 15 large cones. How much money did the store earn?
   ::一家冰淇淋店以2.95美元出售一个小锥体,中型锥体3.50美元出售一个中型锥体,大型锥体4.25美元出售一个大锥体。上星期六,该店出售了22个小锥体,26个中锥体和15个大锥体。该店赚了多少钱?
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10. In Lise’s chemistry class, there are two midterm exams, each worth 30% of her total grade, and a final exam worth 40%. If Lise scores 90% on both midterms and 80% on the final exam, what is her overall score in the class?
    ::在Lise的化学课中,有两个期中考试,每个期中考试都占她全部年级的30%,而期末考试则占40 % 。 如果Lise在两次期中考试中都得90%分,在期末考试中得80%分,她在班中的总分是多少?
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11. The sum of the angles in a triangle is 180 degrees. If the second angle is twice the size of the first angle and the third angle is three times the size of the first angle, what are the measures of the angles in the triangle?
    ::三角形中角度的总和是 180 度。 如果第二个角度是第一个角度的两倍, 而第三个角度是第一个角度的三倍, 那么三角形中角度的量度是多少?
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12. A television that normally costs $120 goes on sale for 20% off. What is the new price?
    ::一台通常花费120美元的电视 以20%的减价出售 新的价格是多少?
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13. A cake recipe calls for $\begin{array}{r}1\frac{3}{4}\end{array}$ cup of flour. Jeremy wants to make four cakes. How many cups of flour will he need?
    ::Jeremy想做四个蛋糕 他需要多少杯面粉?
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14. Kylie is mowing lawns to earn money for a new bike. After mowing four lawns, she still needs $40 more to pay for the bike. After mowing three more lawns, she has $5 more than she needs to pay for the bike.
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    1. How much does she earn per lawn?
       ::她每片草坪挣多少钱?
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    2. What is the cost of the bike?
       ::自行车的成本是多少?
    
    ::Kylie是替新自行车挣钱的草坪。在割了四个草坪后,她仍需要40美元来支付自行车费用。在再割了三个草坪后,她拥有比她需要支付的自行车费用多5美元。她每片草坪挣多少钱?自行车的成本是多少?
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15. Jared goes trick-or-treating with his brother and sister. At the first house they stop at, they collect three pieces of candy each; at the next three houses, they collect two pieces of candy each. Then they split up and go down different blocks, where Jared collects 12 pieces of candy and his brother and sister collect 14 each.
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    1. How many pieces of candy does Jared end up with?
       ::贾雷德到底吃了多少颗糖果?
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    2. How many pieces of candy do all three of them together end up with?
       ::他们三个人在一起 有多少糖果能一起吃?
    
    ::贾里德和他兄妹玩弄或虐待他。在他们停下来的第一所房子里,他们每人收集三块糖果;在接下来的三所房子里,他们每人收集两块糖果。然后他们分成两块,走到不同的街区里,贾里德收集了12块糖果,他兄妹每人收集了14块糖果。贾里德最后拿了多少块糖果?他们三个人一起收集了多少块糖果?
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16. Marco’s daughter Elena has four boxes of toy blocks, with 50 blocks in each one. One day she dumps them all out on the floor, and some of them get lost. When Marco tries to put them away again, he ends up with 45 blocks in one box, 53 in another, 46 in a third, and 51 in the fourth. How many blocks are missing?
    ::马可的女儿Elena有四箱玩具区块,每个区块有50个区块。 有一天,她把它们都扔在地上,有些被丢在地上。 当马可试图再次把它们收起来时,他最后把45个区块放在一个区块中,53个区块在另一个区块中,46个区块在第三个区块中,51个区块在第四个区块中缺失了多少个区块?
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17. A certain hour-long TV show usually includes 16 minutes of commercials. If the season finale is two and a half hours long, how many minutes of commercials should it include to keep the same ratio of commercial time to show time?
    ::某个小时长的电视节目通常包括16分钟的广告。 如果季节末期为2个半小时,那么广告中应该包括多少分钟的时间才能保持商业时间与播放时间的相同比例?
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18. Karen and Chase bet on a baseball game: if the home team wins, Karen owes Chase fifty cents for every run scored by both teams, and Chase owes Karen the same amount if the visiting team wins. The game runs nine innings, and the home team scores one run in every odd-numbered inning, while the visiting team scores two runs in the third inning and two in the sixth. Who owes whom how much?
    ::凯伦和切斯在棒球比赛上下注:如果主队获胜,凯伦欠大通五分钱,两队每分一次,大通欠凯伦五分钱。 如果访问队获胜,那么大通欠凯伦同样多的钱。 比赛打九局,全通队在奇数一局中得一分,而访问队在第三局中得两分,第六局中得两分。谁欠谁多少钱?
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19. Kelly, Chris, and Morgan are playing a card game. In this game, the first player to empty their hand scores points for all the cards left in the other players’ hands as follows: aces are worth one point, face cards ten points, and all other cards are face value. When Kelly empties her hand, Morgan is holding two aces, a king, and a three; Chris is holding a five, a seven, and a queen. How many points does Kelly score?
    ::Kelly、Chris和Morgan正在玩牌游戏。在这个游戏中,第一个为其他玩家手中留下的所有牌清空手记分数的玩家是:A值一分,脸牌十分,而其他所有牌都是面值。 当Kelly举手时,Morgan拿着两张A,一个国王,一个三张;Chris拿着五张,一个七张,一个皇后。Kelly得分多少?
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20. A local club rents out a social hall to host an event. The hall rents for $350, and they hope to make back the rental price by charging $15 admission per person. How many people need to attend for the club to break even?
    ::当地俱乐部租了一个社会大厅来主办一个活动。 大厅租350美元,他们希望通过收取每人15美元的入场费来回扣租金。 俱乐部需要多少人才能实现平衡?
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21. You plan to host a barbecue, and you expect 10 friends, 8 neighbors, and 7relatives to show up.
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    1. If you expect each person (including yourself) to eat about two ounces of potato salad, how many half-pound containers of potato salad should you buy?
       ::如果你期望每个人(包括你自己)吃大约两盎司的土豆沙拉, 那你应该买多少半磅的土豆沙拉?
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    2. If hot dogs come in ten-packs that cost $4.80 apiece and hot dog buns come in eight-packs that cost $2.80 apiece, how much will you need to spend to have hot dogs and buns for everyone?
       ::如果热狗装十包 每人四块八包 热狗包装八包 每人两块八80美元 你们要花多少钱才能给每个人买热狗和包?
    
    ::你计划举办烧烤会,你预期会有10个朋友、8个邻居和7个伙伴出现。如果你期望每个人(包括你自己)吃大约两盎司土豆沙拉,你应该买多少半磅的土豆沙拉? 如果热狗用10包来做10包,每包4美元80美元,热狗面包用8包,每包280美元,每人2美元80美元,你需要花多少钱买热狗和面包?

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Review (Answers)
::回顾(答复)

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Click to see the answer key or go to the Table of Contents and click on the Answer Key under the 'Other Versions' option.
::单击可查看答题键, 或转到目录中, 单击“ 其他版本” 选项下的答题键 。