Question

pens are bought at 12 for a Rupee and sold at 9 for a rupee find the gain %​

Answer 1

Pens are bought at 12 for a rupeeSo cost price of 12 pens = Re. 1

So cost price of 1 pen =Rs.1/12

It is sold at 9 for a rupee

So selling price of 9 pens = Re. 1

So selling price of 1 pen =Rs. 1/9

$gain = \frac{1}{9}- \frac{1}{12} = \frac{4-3}{36}= \frac{1}{36}$

$gain\%= \frac {gain}{CP} \times 100= \frac{1/36}{1/12} \times 100= \frac{12}{36} \times 100= 33.33%$

Gain is 33.33%.