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. 6Total average rate of interest
$$\eqalign{ & {\text{ = }}\frac{{\left( {3 \times 10\% } \right) + \left( {2 \times 9\% } \right) + \left( {1 \times 12\% } \right)}}{6} \cr & = \frac{{\left( {30 + 18 + 12} \right)}}{6} \% \cr & = 10\% \cr} $$
This Question Belongs to Arithmetic Ability >> Interest
The right answer is 10.5% because in solution there is a one mistake, one-third of 3 is one not two. so, (3*10+1*9+2*12)/6 = 10.5%