Question

Simple interest on a certain amount is $\frac{9}{16}$ of the principal. If the numbers representing the rate of interest (in percent) and time (in years) be equal, then time, for which the principal is lent out, is

• A. $5\frac{1}{2}years$
• B. $6\frac{1}{2}years$
• C. 7 years
• D. $7\frac{1}{2}years$

Answer 1

The correct option is D $7\frac{1}{2}years$

$SI=\frac{\text{/}Prt}{100}=\frac{9}{16}\text{/}P$
If r = t $\Rightarrow \frac{r^2}{100}=\frac{9}{16}\Rightarrow r=\sqrt{\frac{100\times 9}{16}}=\frac{30}{4}=7.5\%$
Since r = t t = 7.5 years