A person invested a sum of Rs. 9000 at r% per annum at simple interest and a…
20202020
A person invested a sum of Rs. 9000 at r% per annum at simple interest and a sum of Rs. 13500 at (r-2)% at simple interest. If total interest earned on both the investments for 5 years is Rs. 9337.50, then the rate of interest on the first investment is:
- A.
8%
- B.
10%
- C.
7.5%
- D.
9.5%
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Correct answer: D
Given:
First investment = Rs. 9000 at r%
Second investment = Rs. 13500 at (r − 2)%
Time = 5 years
Total simple interest = Rs. 9337.50
Using SI formula:
SI = (P × R × T)/100
Interest from first investment:
= (9000 × r × 5)/100
= 450r
Interest from second investment:
= (13500 × (r − 2) × 5)/100
= 675(r − 2)
Total interest:
450r + 675(r − 2) = 9337.50
450r + 675r − 1350 = 9337.50
1125r = 10687.50
r = 10687.50/1125
r = 9.5%