Question

Ten copies of the book can be bought for a

certain sum of money payable at the end of 2 years

12 copies of the same book can be bought for the

same sum in ready cash. What is the rate of interest

per annum?

(A) 12 %

(B) l5 %

(c) 10%

(D) 8%​

Answer 1

A 12%is the answer for this

Answer 2

Dear Student,

◆ Answer -

r = 10 %

● Explanation -

Let x be price of one book.

For 10 books, Payable amount after 2 years is -

Payable = P (100 + r×t) / 100

Payable = 10x × (100 + r×2)/100

Payable = 10x + xr/5

For 10 books paid in cash -

Total price = 12 × x

Total price = 12x

Given that, cash price of 12 copies is same as payable after interest of 10 copies.

10x + xr/5 = 12x

12x - 10x = xr/5

2 = r/5

r = 2×5

r = 10 %

Hence, the rate of interest per annum is 10 %.

Thanks dear. Hope this helps you...