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 original sum invested (in Rs)?
This questions was previously asked in
ssc cgl 2023 pre
Explanation:
Correct Option is 4 - Rs 26,000
Solution
Total interest after 18 years = Rs. 35,100
Formula used:
S.I = (P x R x T)/100
Calculation:
Let the principal be 'P'.
For the first 8 years
S.I = (P x 7.25 x 8)/100
⇒ S.I = 58P/100
For the next 6 years
S.I = (P x 8.5 x 6)/100
⇒ S.I = 51P/100
For the next 4 years
S.I = (P x 6.5 x 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.
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By: Parvesh Mehta