A boy bought some bananas at the rate of$10$ bananas for $Rs. 3$ and sold all of them at the rate of $3$ bananas for $Rs. 2$. Find the gain or loss percent.

Mr. Cook sold a book at a profit of $12\%$. If he had sold it for $Rs.1.80$ more, then he would have gained$18\%$. Find the $C.P.$

A man gains $20\%$ by selling an article for $Rs.4.80$. What percent would he have gained or lost had he sold it for $Rs.4.30$?

Mr. $X$ sells an article to $Y$ at a profit of $20\%$ and $Y$ sells it to $Z$ at a profit of $25\%$. If $Z$ buys it for $Rs. 225$, what did $X$ pay for it?

A vendor sells$5$oranges for a Rupee thus gaining $40\%$. How many oranges did he buy for a rupee?

A person sold a watch for $Rs.144$ and got a percentage of profit equal to the cost price. Find the cost price of watch.