A man purchases some oranges at the rate of $3$ for $Rs.\,40$ and the same quantity at $5$ for $Rs.\, 60.$ If he sells all the oranges at the rate of $3$ for $Rs.\, 50,$ find his gain or loss percent (to the nearest integer).

A sells a bicycle to $B$ at a profit of $20 \%.$ B sells it to $C$ at a profit of $25 \%.$ If $C$ pays $Rs.\,225$ for it, the cost price of the bicycle for $A$ is (in $Rs.$)

The value of an article depreciates every year at the rate of $10 \%$ of its value. If the present value of the article is $Rs.\, 729$, then its worth $3\, years$ ago was (in $Rs.$)

A shopkeeper cheats to the extent of $10 \%$ while buying as well as selling, by using false weights. His total gain is in $\%$

A man bought orange at the rate of $8$ for $Rs.\,34$ and sold them at the rate of $12$ for $Rs.\,57.$ How many oranges should be sold to earn a net profit of $Rs.\,45?$

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?