Question

Q.108 identical books have a mass.
of 30 kg . Find.
(i) the mass of 150 such book
(iſ the number of such books that have
a mass of 20kg.​

Answer 1

Answer:

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

Step-by-step explanation:

Answer 2

Answer:

ii) The number of such books that have mass of 20 kg.

Step-by-step explanation:

So we won't go deep and will have a simple solution

Solution:

Using the unitary method.

108 books has a mass of 30kg.

20 kg is a mass of identical books.

108/30 = 1 kg

= 108/30 = 20 kg.

(we will simplify the two zeros. then multiply 108 by 2)

you will get the calculated answer like this 216/3

Divide 216 ÷ 3 = 72

The 72 books has a mass of 20 kg.