The simple interest on a sum of Rs. 8,000 at a certain rate per cent per annum for 3 years is Rs. 3,600. What will be the amount (in Rs.) of the same sum after 2 years at the same rate, if the interest is compounded 8-monthly?

Question

Question

This question was previously asked in

SSC CHSL 2020 Official Paper 19 (Held on: 5 Aug 2021 Shift 1)

Answer 1

Given:

The simple interest on a sum of Rs. 8,000 at a certain rate percent per annum for 3 years is Rs. 3,600.

Concept used:

Simple Interest, SI = (P × R × T) ÷ 100

where

P = Principal amount

R = Rate of interest per year

T = time in years

Compound interest, CI = P(1 + R/100)n - P

where

P = Principal amount

R = Rate of interest per year

N = time in years

Calculation:

Let the rate of interest be R%.

According to the question,

(8000 × R × 3) ÷ 100 = 3600

⇒ R = 15%

Now, the same interest rate would be for compounded 8-monthly = 15 × 8/12 = 10%

So, the amount would become

⇒ 8000 × (1 + 10/100)^24/8

⇒ 10648

∴ Rs. 10648 will be the amount (in Rs.) of the same sum after 2 years at the same rate if the interest is compounded 8 months.