Question

If the cost price of $15$ pens and selling price of $20$ pens are equal, calculate profit or loss in percentage.

Answer 1

Let the C.P. be ${}^{\prime }{x}^{\prime }$ & S.P. be ${}^{\prime }{y}^{\prime }$

then $15x=20y$ ......$\left(1\right)$

As from $\left(1\right)$ $x>y\Rightarrow C.P.>S.P.$

$\therefore$ loss

$\Rightarrow$ Loss$=\frac{C.P-S.P}{C.P}\times 100=\frac{x-y}{x}\times 100$

$\Rightarrow (1-\frac{y}{x})100=(1-\frac{15}{20})100$ .....(from $\left(1\right)$)

$=25\%$ loss.