Question

The cost price of 12 pencils is equal to the selling price of 10 pencils. Find the profit percentage.

Answer 1

Given that, cost price of $12$ pencils is equal to the selling price of $10$ pencils.

To find out: The percentage profit.

Let the cost price of one pencil be $Rs.x$.

$\therefore$ The cost price of $12$ pencils $=12\times x=Rs.12x$.

Also, selling price of $10$ pencils $=Rs.12x$.

Hence, the selling price of one pencil $=Rs.\frac{12x}{10}=Rs.1.2x$

Hence, for one pencil, $C.P.=Rs.x$ and $S.P.=Rs.1.2x$

We know that, $\%\text{profit}=\frac{S.P.-C.P.}{C.P.}\times 100$

$\therefore \%\text{profit}=\frac{1.2x-x}{x}\times 100$

$\Rightarrow \frac{0.2x}{x}\times 100$

$=0.2\times 100$

$=20$

Hence, the required percentage profit is $20\%$.