Question

If in 3 years and at the same rate of interest, the simple interest on ₹2400 is more than the interest on ₹2000 by ₹60. Find the rate of interest.

Answer 1

Let the rate be x% per annum

In first case:
P= $₹2400$
R= $x$%
T= $3$ years
$interest=\frac{P\times T\times R}{100}$
$=₹\frac{2400\times x\times 3}{100}$
$=₹72x$

In second case:
P= $₹2000$
R= $x$%
T= $3$ years
$interest=\frac{P\times T\times R}{100}$
$=₹\frac{2000\times x\times 3}{100}$
$=₹60x$

According to the statement,
$\Rightarrow 72x-60x=60$
$\Rightarrow 12x=60$
$x=\frac{60}{12}$
$\Rightarrow x=5$
$\therefore$ Rate = $5$%