Question

A certain sum of money was lent out at simple interest amounting to rs.690,in three years and rs. 750 in five years. The sum lent out is?

Answer 1

Simple Interest

Given: A certain sum of money was lent out at simple interest amounting to Rs. 690 in three years and Rs. 750 in five years.

To find: The sum lent out

Solution:

Let the sum be Rs. P

• Then interest in 3 years at the rate of r% per year is
• = Rs. P * 3 * r / 100
• = Rs. 3pr/100

• and the interest in 5 years at the same rate is
• = Rs. P * 5 * r / 100
• = Rs. 5pr/100

By the given conditions,

• P + 3pr/100 = 690 .....(1)
• P + 5pr/100 = 750 .....(2)

Now subtracting (1) from (2), we get

• 2Pr/100 = 60
• or, Pr = 3000

Putting Pr = 3000 in (1), we get

P + 9000/100 = 690

or, P + 90 = 690

or, P = 690 - 90

or, P = 600

Answer: The sum lent out is Rs. 600 .