Question

The simple interest and the true discount on a certain sum for a given time and at a given rate are Rs 25 and Rs 20 respectively. The sum is

• A. Rs 500
• B. Rs 200
• C. Rs 250
• D. Rs 100

Answer 1

Answer: (D)

Rs 100

Answer 2

Let that amount be Rs $x$, and rate be r$\%$
Then for simple interest
$\frac{x+r}{100}=25$
$x\times r=2500$
For true discount
$\frac{(x-20)\times r}{100}=20$
$xr-20r=2000$
From equations (i) and (ii), we get
2500-20$r$ = 2000
$r=25\%$
$xr-20r=200$
The correct option is (D)