$A$ person sells $36$ apples per rupee and suffers a loss of $4 \%$. Find how many apples per rupee should be sold to have a gain of $8 \%$.

$A$ person sells $36$ oranges for $₹ 1$ and makes a loss of $4 \%$. Find how many oranges per $₹ 1$ should be sold to have a gain of $8 \%$.

$A$ wholesaler had $200$ dozens of mangoes. He sold some of these mangoes at $20 \%$ profit and the rest at $10 \%$ profit,so that he made $13 \%$ profit on selling all the mangoes. How many mangoes (in dozens) did he sell at $20 \%$ profit?

$A$ man purchased $150$ pens at the rate of $Rs. 12$ per pen. He sold $50$ pens at a gain of $10 \%$. The percentage gain at which he must sell the remaining pens so as to gain $15 \%$ on the whole outlay is........$\%$

If the cost price of $12$ pens is equal to the selling price of $8$ pens,find the gain percent.

By selling an article at $80 \%$ of its marked price,a shopkeeper makes a loss of $10 \%$. What will be the profit percentage if he sells it at $95 \%$ of its marked price (in $\%$)?