Vikkie 發問時間: 社會與文化語言 · 4 年前

How to do? (20 marks)

Mother has 3 1/2 kg of flour, she uses 4/5 of all to bake cakes, and 3/4 of flour to make cookies. How much has been used ?

已更新項目:

2. How many 2/7 's are there in 42 ?

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  • 4 年前
    最佳解答

    圖片參考:https://s.yimg.com/lo/api/res/1.2/ZQit8r6YM3UMER1b...

    Hello~ Vikkie~

    Question 1

    Mother has 3 1/2 kg of flour, she uses 4/5 of all to bake cakes, and 3/4 of the remaining flour to make cookies. How much has been used?

    Note:

    題目有必要更正如上, 因為 4/5 + 3/4 > 1。

    因此不可能兩個分數都是對於整體的 3+1/2 公斤的麵粉。

    Solution:

    The amount of flour which has been used is

    (3 + 1/2) × (4/5) + (3 + 1/2) × (1 - 4/5) × (3/4)

    = (7/2) × (4/5) + (7/2) × (1/5) × (3/4)

    = 28/10 + 21/40

    = 112/40 + 21/40

    = 133/40

    = 3 + 13/40

    = 3 and 13/40 kg

    Question 2

    How many 2/7's are there in 42?

    Solution:

    Consider 42 ÷ (2/7)

    = 42 × (7/2)

    = 21 × 7

    = 84

    There are 84 of 2/7's in 42.

    圖片參考:https://s.yimg.com/rk/HA00430218/o/600258293.jpg

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