章节大纲

  • Appliance Shopping
    ::电器购物

    Now that you are familiar with proportional relationships, and ratios, this lesson will extend that knowledge to ratio problems. In this lesson, you will apply fractions to mark-ups, sale prices, taxes , to determine the answer to different word problems.
    ::既然你熟悉比例关系和比率,这个教训将扩展知识与比率问题。 在这个教训中,你将把分数应用于加价、销售价格、税收,以决定不同字词问题的答案。

    Example
    ::示例示例示例示例

    Your family is remodeling their house and your parents want to get new appliances. They find an online store that is having a sale: 1 4  off all refrigerators, 2 5  off stoves, and 3 10  off dishwashers.  Your parents decide to buy a $1,200 fridge, a $850 stove, and a $450 dishwasher. What are the sale prices for each of these?
    ::你的家庭正在改造他们的房子,而你的父母也想买新的电器。他们发现一家网上商店正在销售:14台冰箱,25台炉子,310台洗碗机。 你的父母决定买1,200美元的冰箱,850美元的炉子,以及450美元的洗碗机。 这些店的销售价格是多少?

    Use the interactive and slide the tape diagram to adjust for each fraction. This will help you determine the discount . Then, subtract the discount from the original price to get the sale price.
    ::使用交互式和幻灯片磁带图来调整每个分数。 这将帮助您确定折扣。 然后, 从原始价格中减去折扣以获得销售价格 。

     

    INTERACTIVE
    Appliance Shopping
    minimize icon
    • Move the green slider to set the starting price.
      ::移动绿滑块以设定起始价格 。
    • Move the red and blue sliders to set the discount ratio.
      ::移动红色和蓝色滑块以设定贴现率 。
    • The discount price is displayed in black.
      ::贴现价格以黑色显示。
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    1.

    How can you determine the amount that the stove is discounted? Select all answers that apply.
    ::您如何确定炉灶折扣的金额? 选择所有适用的答案 。

    Select all that apply
    a

    Multiply $850 by 5, then divide by 2.
    ::850美元乘以5,再除以2。

    b

    Divide $850 by @$\begin{align*}\tfrac{2}{5}.\end{align*}@$
    ::除以 850 美元@$\ begin{ align} tfrac{ 2\\\ 5}.\ end{ align} $

    c

    Divide $850 by 5, then multiply by 2.
    ::除以850除以5,再乘以2。

    d

    Multiply $850 by @$\begin{align*}\tfrac{2}{5}.\end{align*}@$
    ::乘以 850 美元@$\ begin{ align} $\ tfrac{ 2\\ 5} 。\ end{ align} $

     

    Don't forget, in order to change a percent to a decimal, you need to move the decimal point 2 places to the left. 
    ::不要忘了,为了将百分比变为小数点, 您需要将小数点点 2 移到左边 。

    For all of these problems, you multiplied the cost by the fraction to get the amount off of the appliance. Then, you subtracted that from the original amount to get the sale price. As question #3 points out, there is another way to do this type of problem. Instead of multiplying by the discount fraction that you were given, you could multiply by   ( 1 − discount fraction ) .
    ::对于所有这些问题,您会将成本乘以分数,从电器中取出数量。 然后,您会从原来的金额中减去这笔金额,以获得销售价格。 正如问题3所指出的,还有另一种方法可以解决这类问题。与其乘以给您提供的折扣分数,不如乘以(1-折扣分数 ) 。

     

    Clothes Shopping
    ::服装购物

    Most clothing stores will mark-up the cost of an item, only to mark it back down to make it appear that it is on sale. They do this to make the consumer feel like they are getting a better deal and to make more money. One particular store, Wood's Clothing, does this all the time!  Consistently, they will mark-up women's shirts by  3 2  and then take  1 4  off. If the initial cost of the shirt is $24, how much will the consumer (you) end up paying for it?
    ::大部分服装店都会给一件物品的价钱加分, 只是为了给它打上印记, 让它看起来在出售。 他们这样做是为了让消费者觉得他们正在得到更好的交易和赚更多的钱。 一家特定的商店, 伍德服装店, 总是这样! 一贯地, 她们会在32美元前加分妇女衬衫, 然后把14件脱光。 如果衬衫的最初价格是24美元, 那么消费者( 你)会付出多少钱呢?

     

    INTERACTIVE
    Clothes Shopping
    minimize icon
    • Move the green slider to set the starting price.
      ::移动绿滑块以设定起始价格 。
    • Move the red and blue sliders to set the discount or markup ratio.
      ::移动红色和蓝色滑块以设定折价或加分比率 。
    • The new price is displayed in black.
      ::新价格以黑色显示 。
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    Discussion Question
    ::讨论问题

    Discuss why you think stores would implement this mark-up scheme. Why do stores mark-up clothes as much as they do?
    ::讨论你为什么认为商店会执行这个加价计划。为什么商店会像它们一样多加价衣服呢?

    for other examples of mark-ups!
    ::其他加注的例子!

    Recall that dividing by a fraction is the same as multiplying by its reciprocal . In addition, to undo an operation in math, you need to work backwards and perform the opposite operation. The opposite of multiplication is division and the opposite of addition is subtraction. 
    ::提醒大家注意,除以分数等于乘以对等值。此外,要取消数学操作,您需要倒着工作,执行相反的操作。乘法的反面是除法,加法的反面是减法。

       Summary
    ::摘要

    • To find a sale price, you can either: Multiply the original price by the discount fraction to find the size of the discount. Then subtract that discount from the original price, or multiply the original price by (1 − discount fraction).
      ::要找到销售价格,您可以要么:将原始价格乘以贴现分数以找到贴现的大小。然后从原始价格中减去这一折扣,要么将原价格乘以(1 - 贴现分数)。
    • To change a percent to a decimal, move the decimal point to the left two places.
      ::要将百分比修改为小数点,将小数点移到左两个位。
    • To undo operations in math, perform the opposite operation.
      ::要取消数学中的操作, 执行相反的操作 。