A sum of money earns a simple interest at 7.25% per annum for the first eight years, at 8.5% for the next six years, and at 6.5% for the final four years. If the total interest earned during these eighteen years was Rs. 35,100, what was the original sum invested (in Rs.)?

Question

Question

This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 20 Jul 2023 Shift 2)

Answer 1

Given:

Total interest after 18 years = Rs. 35,100

Formula used:

S.I = (P × R × T)/100

Calculation:

Let the principal be ‘P’.

For the first 8 years

S.I = (P × 7.25 × 8)/100

⇒ S.I = 58P/100

For the next 6 years

S.I = (P × 8.5 × 6)/100

⇒ S.I = 51P/100

For the next 4 years

S.I = (P × 6.5 × 4)/100

⇒ S.I = 26P/100

Total Interest in 18 years = Rs. 35,100

(58P/100) + (51P/100) + (26P/100) = 35100

⇒ 135P/100 = 35100

⇒ P = 26000

∴ The amount invested is Rs. 26,000.