A certain sum amounts to Rs. 10164 in 4 years and to Rs. 12320 in 7 years at the same rate of interest per annum at simple interest. The sum and the rate of interest are, respectively?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. Rs. 7700 and 8%
Given:
A certain sum amounts to Rs. 10164 in 4 years and to Rs. 12320 in 7 years at the same rate of interest per annum at simple interest
Formula used:
SI = PRT/100 ---- (1)
Where, SI = Simple interest, P = principal, R = rate and T = time
Calculations:
Simple interest for 3(1/2) years = (12320 - 10164) = Rs 2156
Simple interest for 1 year = 2156/3.5 = Rs 616
Simple interest for 4 years = Rs 2464
Principal = 10164 - 12320 = Rs 7700
Using equation (1), we get
⇒ 616 = (7700 × 1 × R)/100
⇒ R = 8%