$A$ toothpaste labeled at $Rs. 80$ is sold for $Rs. 68$. The rate of discount is.......$\%$

$A$ sells his house worth $Rs. 10\, lakh$ to $B$ at a loss of $10\%$. Later,$B$ sells it back to $A$ at $10\%$ profit. The result of the two transactions is:

$A$ trader marked his goods at $20 \%$ above the cost price. He sold half the stock at the marked price,one quarter at a discount of $20 \%$ on the marked price,and the rest at a discount of $40 \%$ on the marked price. His total gain is.......$\%$

The list price of a book is $Rs. 100$. $A$ dealer sells three such books for $Rs. 274.50$ after allowing a discount at a certain rate. Find the rate of discount in $\%$.

By selling an article for $Rs. 144$,a person gained such that the percentage gain equals the cost price of the article. The cost price of the article is (in $Rs.$):

Sudeep buys two $CDs$ for $Rs. 380$ and sells one at a loss of $22 \%$ and the other at a gain of $12 \%$. If both the $CDs$ are sold at the same price,then the cost price of the two $CDs$ is (in $Rs.$)