Question

A man sells $5$ identical articles for $Rs.15$ and makes a profit of $20\%$. Find his gain or loss per cent; if he sells $8$ such articles for $Rs.18.40$.

Answer 1

S.P of $5$ article=$Rs15$.
S.P of $1$ article =$\frac{15}{5}=3Rs.$
Profit = $20\%$
Then C.P.=$\frac{100}{120}\times 3=2.5Rs.$
now C.P of $1$ article = $Rs.2.5$
then CP of $8$ article=$2.5\times 8=20.0Rs.$
S.P of $8$ article=$Rs.18.40$.
$Loss=C.P-S.P=20-18.40=1.60Rs.$
$Profitpercentage=\frac{1.60}{20}\times 100=8$