In a certain store, the profit is $320 \%$ of the cost. If the cost increases by $25 \%$ but the selling price remains constant, approximately what percentage of the selling price is the profit?

Ramesh purchased a bicycle for $Rs.\,5200$ and spent $Rs.\,800$ on its repairs. He had to sell it for $Rs.\,5500.$ Find out his profit or loss percent.

A shopkeeper sells notebooks at the rate of $Rs.\,457$ each and earns a commission of $4 \% .$ He also sells pencil boxes at the rate of $Rs.\,80$ each and earns a commission of $20 \% .$ How much amount of commission will he earn in two weeks if he sells $10$ notebooks and $6$ pencil boxes a day?

Arun purchased $30\, kg$ of wheat at the rate of $Rs.\,11.50$ per $kg$ and $20\, kg$ of wheat at the rate of $Rs.\,14.25$ per $kg$. He mixed the two and sold the mixture. Approximately at what price per $kg$ should he sell the mixture to make $30 \%$ profit? (in $Rs.$)

By what fraction selling price $(S.P.)$ must be multiplied to get the cost price $(C.P.)$ if the loss is $20 \% ?$

If the ratio of the cost price and selling price of an article is $20: 21,$ then what will be the profit percent?