Question

If the amount after Simple Interest on a sum of $\text{Rs.}10,000$ at $5\%$ per annum is $\text{Rs.}50,000$. Find the time for which the interest is computed.

• A. $10$ years
• B. $40$ years
• C. $80$ years
• D. $100$ years

Answer 1

The correct option is C

$80$ years

Given, Principal $=\text{Rs.}10,000$

Rate $=5\%$

Let the time for which the interest is computed be $t$ years

Amount $=\text{Rs.}50,000$

Since, Amount $=$ Simple Interest $+$ Principal

$\Rightarrow$ Simple Interest $=$ Amount $-$ Principal

$\Rightarrow$ Simple Interest $=50,000-10,000=\text{Rs.}40,000$

Now, since, Simple Interest $=\frac{\text{P}\times \text{r}\times t}{100}$

$\Rightarrow 40,000=\frac{10,000\times 5\times t}{100}$

$\Rightarrow t=\frac{40,000\times 100}{10,000\times 5}$

$\Rightarrow t=80$ years