Mahesh purchased $25\, kg$ of rice at $32$ per $kg$ and $15\, kg$ of rice at $Rs\,.36$ per $kg.$ He mixed the two varieties of rice and sold it at $Rs.\, 40.20$ per $kg.$ What is the percent profit earned?

A discount dealer professes to sell his goods at cost price but uses a weight of $960\, gms$ instead of a $Kg$ weight. Find his gain $\% ?$

Anil bought an item with $12 \frac{1}{2} \%$ discount on the labellea price. He sold the item with $17 \frac{1}{2} \%$ profit on the labelled price. What was, his percent profit on the price he bought?

Sudeep buys two $CDs$ for $Rs.\,380$ and sells one at a loss of $22 \%$ and the other at a gain of $12 \%$. If both the $CDs$ are sold at the same price, then the cost price of two $CDs$ is (in $Rs.$)

A trader buys good at $20 \%$ discount on marked price. If he wants to make a profit of $25 \%$ after allowing a discount of $20 \%$, by what percent should his marked price be greater than the original marked price?

Aditya purchase a book with a $20 \%$ discount on the marked price. How much $Rs.$ did he pay if the book marked was $Rs.$ $500 ?$