$A$ fruit vendor buys $10$ bananas for $Rs. 14$ and sells them at $12$ for $Rs. 15$. Find his percentage gain or loss.

$A$ shopkeeper sold an article for $Rs. 400$ after giving a $20\%$ discount on the labelled price and made a $30\%$ profit on the cost price. What would have been the percentage profit,had he not given the discount (in $\%$)?

Harkesh bought a certain quantity of tomato at the rate of $Rs. 1500$ per quintal. $10 \%$ of the tomato was spoiled. At what price in $Rs.$ per quintal should he sell the remaining to gain $20 \%$ of his outlay?

$A$ person bought an article for $Rs. 240$. For how much should he sell it so as to lose $20\%$?

$A$ man sells a scooter to his friend at $10\%$ loss. If the friend sells it for $₹ 54000$ and gains $20\%$,find out the original cost price of the scooter. (in $₹$)

$A$ shopkeeper allows a discount of $10\%$ on the marked price of an item but charges a sales tax of $8\%$ on the discounted price. If the customer pays $Rs. 3,402$ as the price including the sales tax,then the marked price is (in $Rs.$)