Question

On selling $100$ pencils a man gains the selling price of $20$ pencils. His gain percent is
(a) $20\%$

(b) $25\%$

(c) $22\frac{1}{2}\%$

(d) $16\frac{2}{3}\%$

Answer 1

The correct option is (b): $25\%$

Let the SP of $100$ pens be $Rs.x$

SP of $1$ pen $=Rs.\frac{x}{100}$

Profit $=$ SP of $20$ pencils $=Rs.\frac{20x}{100}=Rs.\frac{x}{5}$

Now, CP $=$ SP $-$ profit $=x-\frac{x}{5}=\frac{4x}{5}$

$\therefore$ Gain percentage $=\frac{Gain}{CP}\times 100\%=\frac{\frac{x}{5}}{\frac{4x}{5}}\times 100=25\%$