By selling 80 ball pens for $Rs.\, 140$ a retailer loses $30 \%$. How many ball pens should he sell for $Rs.\, 104$ so as to make a profit of $30 \% ?$

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

A dealer sold a bicycle at a profit of $10 \% .$ Had he brought the bicycle at $10 \%$ less price and sold it at a price $Rs.\, 60$ more, he would have gained $25 \%$. The cost price of the bicycle was

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 in $\%$?

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

A businessman allows a discount of $10 \%$ on the marked price. What percent above the cost price must he mark his goods to make a profit of $17 \% ?$