MCQ 11 Mark
In how many years will a certain sum become $3$ times itself at $25\%$ per annum under simple interest?
- A$5$
- ✓$8$
- C$12$
- D$6$
Answer
View full question & answer→Correct option: B.
$8$
Amount $= 3$ times the sum $= 3P$
Simple interest $(I)$ = Amount - Sum $= 3P - P = 2P$
Let the sum $(P)$ be $x$.
Then, simple interest $(I) = 2x$
Rate $(R) = 25\%$
Time $= T$
$\text{I}=\frac{\text{P}\ \times\ \text{R}\ \times\ \text{T}}{100}$
$\Rightarrow\text{T}=\frac{100\ \times\ \text{I}}{\text{P }\times\text{ R}}$
$=\frac{100\ \times\text{ 2x}}{\text{x } \times\ 25}$
$=8\%$
Hence, the correct option is $(b)$.
Simple interest $(I)$ = Amount - Sum $= 3P - P = 2P$
Let the sum $(P)$ be $x$.
Then, simple interest $(I) = 2x$
Rate $(R) = 25\%$
Time $= T$
$\text{I}=\frac{\text{P}\ \times\ \text{R}\ \times\ \text{T}}{100}$
$\Rightarrow\text{T}=\frac{100\ \times\ \text{I}}{\text{P }\times\text{ R}}$
$=\frac{100\ \times\text{ 2x}}{\text{x } \times\ 25}$
$=8\%$
Hence, the correct option is $(b)$.