$A$ vendor buys bananas at $9$ for $Rs. 8$ and sells at $8$ for $Rs. 9$. What will be the profit or loss (in $\%$)?

$A$ man sells each of his $2$ articles for $Rs. 99$. On one he gains $10 \%$ and on the other he incurs a loss of $1 \%$. What is his total gain in $\%$ in the entire transaction?

$A$ shopkeeper gains $17 \%$ after allowing a discount of $10 \%$ on the marked price of an article. Find his profit percent if the article is sold at the marked price allowing no discount. (in $\%$)

Find a simple discount equivalent to a discount series of $10 \%, 20 \%$ and $25 \%$ (in $\%$).

$A$ shopkeeper sold chairs at $Rs. 2139$ each after giving a $7 \%$ discount on the labelled price. Had he not given the discount, he would have earned a profit of $15 \%$ on the cost price. What was the cost price of each chair? (in $Rs.$)

Aditya sold a $TV$ to Sanjay at $12 \%$ more than the $CP.$ If Sanjay paid $Rs. 17696$ for that $TV,$ then what was the original price $(CP)$ of the $TV$ in $Rs.$?