Question

A certain number of articles are bought at $3$ for $₹150$ and all of them are sold at $4$ for $₹180$. Find the loss or gain as percent.

Answer 1

L.C.M. of $3$ and $4=12$
Let $12$ articles are bought
$\therefore$ C.P. of $12$ articles $=\frac{150\times 12}{3}=600₹$
And S.P. of $12$ articles $=\frac{180\times 12}{4}=540₹$
Loss $=$ C.P. $-$ S.P.
$=(600-540)₹$
$=60₹$
Loss $\%=\frac{\text{Loss}\times 100}{\text{C.P.}}$
$=\frac{60\times 100}{600}$
$=10\%$