Question 11 Mark
In how many years will a certain sum become 3 times itself at 25% per annum under simple interest?
- 5
- 8
-
12
-
6
Answer
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).
View full question & answer→- 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).