Question

The selling price of $15$ articles is equal to the cost price of $12$ articles. Find the gain or loss as percent.

Answer 1

Let C.P. of $1$ article = $Rs.1$
$\therefore$ C.P. of $12$ article = $Rs.12$
and C.P. of $15$ articles = $Rs.15$

From question,

S.P. of $15$ articles = C.P. of $12$ articles
$\therefore$ S.P. of $15$ articles $=Rs.12$
Since S.P $<$ C.P, so its loss.

Lets evaluate loss
Loss $=Rs.15-Rs.12=Rs.3$
Loss in $\%=\frac{\text{loss}}{S.P}\times 100$
Loss in $\%=\frac{3}{15}\times 100$
$=\frac{3\times 100}{15}$
Therefore, loss in percent is $20\%$.