A student buys a pen for Rs. 90 and sells it for Rs. 100. Find his gain and gain percent.

Explanation

A student buys a pen for Rs `90` and sells it for Rs `100`.
Gain= S.p-C.p=`100-90`
=Rs.`10`.
Gain` %=( S.P-C.P)/(C P) *100`
Gain`%=(10/90)xx100`
`=100/9%`
`=11.1%`