The cost price of $100$ books is equal to the selling price of $60$ books. The gain percentage or loss percentage is:

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 $Rs.$?

Aditya bought $200$ dozen oranges at $Rs. 10$ per dozen and he spent $Rs. 500$ on transportation. He sold each orange at $Rs. 1$ each. What was his profit or loss $\%$?

$A$ man buys $100 \, kg$ of sugar for $Rs. \, 2400$. He sold $1/4$th of the stock at a loss of $5 \%$. At what per cent profit should he sell the remaining stock so as to make an overall profit of $20 \%$ on the whole transaction? (in $\%$)

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

Successive discounts of $10 \%$,$20 \%$ and $50 \%$ will be equivalent to a single discount of .......... $\%$