If theselling price of 10 pens is equal to cost price of 14 pens, find the gain percent.

A dealer buys a wristwatch for Rs 225 and spends Rs 15 on its repairs. If he sells the same for Rs 300, find his profit percent.

Ramesh bought two boxes for Rs 1300. He sold one box at a profit of 20% and the other box at a loss of 12%. If the selling price of both boxes is the same, find the cost price of each box.

If the selling price of 18 chairs be equal to selling price of 16 chairs, find the gain or loss percent.

If the selling price of 18 oranges is equal to the cost price of 16 oranges, find the loss percent.