Question

The cost of 8 books is ₹72, then the cost
of 20 such books

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Cost of 8 books = ₹ 72

Cost of one book = ₹ 72/8 = ₹9

→ Cost of 20 books = ₹ (9 × 20) = ₹ 180

Alternative Method : (Proportion method)

Let the cost of 20 books be ₹ x.

8/72 = 20/x

→ 8 × x = 20 × 72

[Product of extremes = Product of means]

→ x = 20×72/8 = 180

Hence, the cost of 20 books is ₹ 180.