A boy buys 9 apples for Rs 9.60 and sells them at 11 for Rs 12. Find his gain or loss percent.

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

Rekha bought a saree for Rs 1240 and sold it for Rs 1147. Find her loss and loss percent.

The cost price of 10 articles is equal to the selling price of 9 articles. Find the profit percent.

A retailer buys a radio for Rs 225. His overhead expenses are Rs 15. If he sells the radio for Rs 300, determine his profit percent.