A man invests half of his capital at the rate of 10% per annum, one - third at 9% and the rest at 12% per annum. The average rate of interest per annum, which he gets is = ?

A. 9%

B. 10%

C. 10.5%

D. 12%

Answer: Option B

Solution(By Examveda Team)

Let the total amount = Rs. 6
Total average rate of interest
$$\eqalign{ & {\text{ = }}\frac{{\left( {3 \times 10\% } \right) + \left( {2 \times 9\% } \right) + \left( {1 \times 12\% } \right)}}{6} \cr & = \frac{{\left( {30 + 18 + 12} \right)}}{6} \% \cr & = 10\% \cr} $$