$'A ^{\prime}$ sells an article to $'B ^{\prime}$ at a gain of $20 \%$ and $' B ^{\prime}$ sells it to $'C ^{\prime}$ at a gain of $10 \%$ and $'C ^{\prime}$ sells it to $'D'$ at a gain of $12 \frac{1}{2} \%$. If ${ }^{\prime} D$ ' pays $Rs.\, 29.70$ what did it cost to $'A ^{\prime} ?$ (in $Rs.$)

Tarun bought a $TV$ with $20 \%$ discount on the labelled price. Had he bought it with $25 \%$ discount, he would have saved $Rs.\,500.$ At what price did he buy the $TV?$

A shopkeeper purchased a chair marked at $RS.\, 600$ at two successive discounts of $15 \%$ and $20 \% .$ He spent $Rs.\, 28$ on transportation and sold the chair for $Rs.\,545.$ His gain percent was

The cost price of $6$ pens is equal to the selling price of $4$ pens. Find the profit percent.

If the $CP$ of $13$ bats is $Rs.$ $390 .$ What is the price in $Rs.$ when it is sold at $10 \%$ loss?

By selling $25$ $metres$ of cloth a trader gains the selling price of $5$ $metres$ of cloth. The gain of the trader in $\%$ is