$A$ shopkeeper loses $7 \%$ by selling a cricket ball for $Rs. 31$. For how much should he sell the ball so as to gain $5 \%$? (in $Rs.$)

On selling $17$ balls at $Rs. 720$,there is a loss equal to the cost price of $5$ balls. The cost price of a ball is (in $Rs.$)

$A$ shopkeeper sells one transistor for $Rs.\, 840$ at a gain of $20 \%$ and another for $Rs.\, 960$ at a loss of $4 \%$. His total gain or loss percent is

$A$ shopkeeper gains $17 \%$ after allowing a discount of $10 \%$ on the marked price of an article. Find his profit percent if the article is sold at the marked price allowing no discount. (in $\%$)

Aditya bought a scooter for a certain sum of money. He spent $15 \%$ of the cost price on repairs and sold it for a profit of $Rs. 1104$. What did he spend on repairs if the profit he earned was $20 \%$?

$A$ businessman allows a discount of $10 \%$ on the marked price. What percent above the cost price must he mark his goods to make a profit of $17 \% ?$