Question

A man invested Rs. $1000$ on simple interest at a certain rate and Rs. $1500$ at $2\%$ higher rate. The total interest in three years is Rs. $390$. What is the rate of interest for Rs. $1000$?

• A. $4\%$.
• B. $5\%$.
• C. $6\%$.
• D. $7\%$.

Answer 1

Answer: (A)

$4\%$.

Let the interest rate at which $Rs.1000$ is invested is $r\%$
Then Rs. $1500$ is invested at $(r+2)\%$

Then according to the question, we have
$\frac{1000\times r\times 3}{100}+\frac{1500\times (r+2)\times 3}{100}=390$

$\Rightarrow 30r+45r+90=390$
$\Rightarrow 75r=300$

$\Rightarrow r=4\%$