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

(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~ :)

Ans.

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

Please correct me!

a) 108=30 kg

As we do not know the mass of 150 books, we will let it as x so:
150=x
Now we will cross multiply.
108=30
×
150=x
180x=150×30
180x=4500
x =4500÷108
x =41.67kg

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

(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

Divide 30 by 108 = 5 by 18

5 by 15 multiply by 150 = 41.23 kg
=41 2/3 kg is the Answer!

Its correct, btw thanks a lot🤓

Correct answer

Correct methods

It is amazing

It's right but I want unitary method