$A$ single discount,equivalent to a successive discount of $40 \%$ and $30 \%$ is in $\%$?

Amit purchased $13$ chairs for $Rs. 115$ each and sold all of them for $Rs. 1220$. Find the profit or loss on the transaction.

$A$ shopkeeper bought $30 \text{ kg}$ of wheat at the rate of $₹ 45$ per $\text{kg}$. He sold $40\%$ of the total quantity at the rate of $₹ 50$ per $\text{kg}$. Approximately,at what price per $\text{kg}$ should he sell the remaining quantity to make $25\%$ overall profit? (in $₹$)

$A$ shopkeeper sold some articles at $Rs. 35$ per piece and gained $40 \%$. What would be the selling price of each article to earn $60 \%$ profit? (in $Rs.$)

$A$ trader buys goods at a $20 \%$ discount on the marked price. If he wants to make a profit of $25 \%$ after allowing a discount of $20 \%$ on his new marked price,by what percent should his new marked price be greater than the original marked price?

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