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 ₹35,100, what was the original sum invested (in ₹)?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 26,000.
We know that
S.I. = (P × 7.25 × 8)/100
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 = Rs.26000