Math

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A pile of 108 identical books has a mass of 30 kg.
Find
(a)the mass of 150 books and
(b)the number of books that has a mass of 20 kg

  • Math -

    (a) to get this, we just use ratio and proportion:
    let x = weight of 150 books.
    108 books : 30 kg = 150 books : x kg
    we can thus rewrite this as
    108/30 = 150/x
    3.6 = 150/x
    x = 150/3.6
    x = 41.67 kg

    (b) we also use ratio and proportion here:
    let y = number of books that has weight of 20 kg.
    108 books : 30 kg = y books : 20 kg
    thus,
    108/30 = y/20
    3.6 = y/20
    y = 3.6*20
    y = 72 books

    hope this helps~ :)

  • Math -

    (a)
    the mass of 108 books=30 kg
    the mass of one book=30/108
    the mass of 150 books=150*5/8
    =125/8 kg

  • Math -

    Ans.
    30/108=5/18
    5/15 x 150=41. 2/3kg

    Please correct me!

  • Math -

    (a)150/108=a/30
    108*a=150*30
    150*30/108
    75*15/27
    1125/27
    41.66
    (b)108/a=30/20
    3a=10821*2
    108*2/3a
    216/3=72

  • Math -

    Sorry if this is not the answer , thank you !! it helps me sooo much !!

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