Question

The simple interest on a certain sum computes to Rs. 600 in 3 years and the compound interest. on the same sum, at the same rate and for 2 years computes to Rs. 410. Find the rate percent.

• A. 5%
• B. 6%
• C. 7%
• D. 8%

Answer 1

The correct option is A 5%

Since, S.I. of 3 years $=$ Rs. 600
$\therefore$ S.I. of 1 years $=Rs.\frac{600}{3}=Rs.200$ [S.I is same every year]
$\therefore$ C.I. for first year $=$ Rs. 200 [For 1st year: C.I. $=$ S.I.]
Given, C.L for two years $=$Rs. 410
$\therefore$ C.I. for 2nd year $=$ Rs. 410 - Rs. 200 $=$Rs. 210.
Difference between the C.I. of two successive years $=$Rs. 210 - Rs. 200 $=$ Rs. 10
$\Rightarrow$ Rs. 10 is the interest for one year on the interest of 1st year i.e. on Rs. 200
$\therefore$ Rate % $=\frac{100\times I}{P\times T}\%=\frac{100\times 10}{200\times 1}\%=5\%$ Ans.