Q52
The simple interest on a sum of money is 4/9 of the principal and the number of years is equal to the rate percent per annum. The rate per annum is = ?
The simple interest on a sum of money is of the principal and the number of years is equal to the rate percent per annum. The rate per annum is = ?
A.
5%
B.
%
AnswerC.
6%
D.
%
Answer: Option B
Solution
Answer: Option B
Solution:
\begin{aligned}
& {\text{Let the principal}} \\
& {\text{ = 9 units }} \\
& {\text{Hence simple interest}} \\
& {\text{ = }}\frac{4}{9} \times {\text{9 = 4 units}} \\
& {\text{Let,}} \\
& {\text{Rate of interest = R% }} \\
& {\text{R = T (given)}} \\
& {\text{By using formula}} \\
& \boxed{{\text{SI = }}\frac{{{\text{P}} \times {\text{T}} \times {\text{R}}}}{{100}}} \\
& 4 = \frac{{9 \times {\text{R}} \times {\text{R}}}}{{100}} \\
& {{\text{R}}^2} = \frac{{400}}{9} \\
& {\text{R = }}\frac{{20}}{3} = 6\frac{2}{3}\% \\\end{aligned}