Arun marks up the computer he is selling by $20 \%$ profit and sells them at a discount of $15 \%$. Arun's net gain percent is (in $\%$)

The cost price of an article is $80 \%$ of its marked price for sale. How much percent does the tradesman gain after allowing a discount of $12 \%$?

$A$ trader marked the selling price of an article at $10 \%$ above the cost price. At the time of selling,he allows a certain discount and suffers a loss of $1 \%$. He allowed a discount of $\%$:

$A$ 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 $8 \%$.

$A$ shopkeeper professes to sell his goods at cost price but uses a $930 \text{ g}$ weight instead of $1 \text{ kg}$ weight. What will be the profit percentage of the shopkeeper (in $\%$)?

The price of $12$ chairs and $8$ tables is $Rs. 676$. What is the price of $21$ chairs and $14$ tables in $Rs.$?