Question

Pens are bought at 12 for a rupee and sold at 9 for a rupee. Find the gain or loss%.

Answer 1

Pens are bought at $12$ for a rupee sold at $9$ for a rupee. Find the gain or loss $\%$.

Pens are bought of $12$ for a rupee

Cost price(c.p) of the $12$ pens$=$Re. $1$

Cost price (c.p) of $1$ pen$=$Rs. $\frac{1}{12}$

Now,

Selling price(s.p) of $9$ pens$=$Re. $1$

Selling price(s.p) of $1$ pen$=$Rs. $\frac{1}{9}$

Gain$=s.p-c.p$

$=$Rs. $[\frac{1}{9}-\frac{1}{12}]$

$=$Rs. $\left[\frac{4-3}{36}\right]=$Rs. $\frac{1}{36}$

Gain$\%=\frac{Gain}{c.p}\times 100=\frac{\frac{1}{36}}{\frac{1}{12}}\times 100=\frac{12}{36}\times 100$

$=\frac{100}{3}$

$=33.33\%$.