Question

Ajeet lent Rs. 4000 to Bunty for 3 years and Rs.5000 to Chintu for 4 years on simple interest at the same rate of interest and received Rs. 3200 total from both as interest. Then find the rate of interest per annum.

1. 15% 
2. 10% 
3. 20%
4. 5 %

Answer 1

Correct Answer - Option 2 : 10% 

Given:

Principal for Bunty = Rs. 4000

Principal for Chintu = Rs. 5000

Time period for Bunty = 3 years

Time period for Chintu = 4 years

Total Simple Interest = Rs. 3200

Formula used:

Simple Interest = (Principal × Rate × Time)/100

Calculation:

3200 = [(4000 × Rate × 3)/100] + [(5000 × Rate × 4)/100]

⇒ (120 × Rate) + (200 × Rate) = 3200

⇒ 320 × Rate = 3200

⇒ Rate = 10%

∴ The rate of interest per annum is 10%.