Amit buys $5$ watches for $Rs. 9450$ and later sells them for $Rs. 9700$. How much profit does Amit make per watch in $Rs.$?

An $Ox$ and a carriage together cost $Rs. 8000$. The ox is sold at a profit of $10\%$ and the carriage is sold at a loss of $10\%$. If the total profit made is $2.5\%$,then what is the cost price of the ox? (in $Rs.$)

$A$ trader buys $500 \, kg$ of cotton for $Rs. 9,000$. $10 \%$ of this cotton is spoiled due to rain. At what rate $(Rs./ kg)$ should he sell the rest to earn $10 \%$ profit?

An article is marked for sale at $Rs. 504$. The shopkeeper gives a discount of $5\%$ on the marked price and still earns a profit of $20\%$. What is the cost price of the article? (in $Rs.$)

$A$ man bought $15$ mangoes for a rupee. How many mangoes were sold for a rupee so that there is a loss of $25 \% ?$

Profit earned by selling an article for $Rs. 1630$ is the same as the loss incurred by selling the article for $Rs. 1320$. What is the $CP$ in $Rs$?