The simple interest on a certain sum at the end of three years at 5 p a is Rs1 200 The compound inte...........

Quantitative Aptitude (CGL) Simple Interest

The simple interest on a certain sum at the end of three years at 5%p.a. is Rs1,200. The compound interest on the same sum

for the same period at the same rate is (interest compounded yearly):

This questions was previously asked in

SSC CGL 3rd March 2020 Shift-3

Rs1,800

Rs1,261

Rs820

Rs1,260

Let's break it down:

- First, we have simple interest (SI) = Rs 1,200 for 3 years at 5% per year.

- To find the principal:

SI = (P × R × T)/100 ? 1200 = (P × 5 × 3)/100

That gives us P = (1200 × 100) / (5 × 3) = Rs 8,000.

- Now, we have to find compound interest (CI) for 3 years, same sum and rate, compounded yearly.

- CI = P[(1 + R/100)^T – 1]

CI = 8,000 × [(1 + 0.05)^3 – 1]

Let's compute that:

- (1.05)^3 ˜ 1.157625

- That means CI = 8,000 × (1.157625 – 1) = 8,000 × 0.157625 ˜ Rs 1,261

- Option 2, Rs 1,261, matches our calculation.

- The other options don’t check out mathematically:

- 1,800 is way too high, not possible at 5%

- 820 is less than the simple interest, which can't happen in compound interest

- 1,260 is very close, but the nearest accurate figure is 1,261

So, Option 2 – Rs 1,261 is correct.

Submit Error