A man gains $15 \%$ by selling a calculator for a certain price. If he sells it at the triple the price, then what will be the profit percentage?

A sells an article to $B$ at a profit of $20 \%$ and $B$ sells it to $C$ at a loss of $10 \% .$ If $C$ pays $Rs.\,540$ for it, at what price did A buy?

A shopkeeper bought $30\, Kg$ of wheat at the rate of $Rs.\,45$ per $Kg.$ He sold $40\%$ of the total quantity at the rate of $Rs.\,50$ per $Kg.$ Approximately, at what price per $Kg$ should he sell the remaining quantity to make $25$ percent overall profit? (in $Rs.$)

An article is sold at a certain fixed price. By selling it at $\frac{2}{3}$ of that price, one loses $10 \%$. The gain percent on selling it at the original price is

Albert buys $4$ $horses$ and $9$ cows for $Rs. 13400$. If he sells the horse at $10 \%$ profit and the cows at $20 \%$ profit, then he earns a total profit of $Rs.\, 1880 .$ The cost of a horse is (in $Rs.$)

A vendor bought toffees at $6$ for a rupee. How many for a rupee must he sell to gain $20 \% ?$