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

$A$ trader marked the price of his commodity so as to include a profit of $25 \%$. He allowed a discount of $16 \%$ on the marked price. His actual profit was (in $\%$):

The ratio of cost price and selling price of an article is $25:26$. The percent of profit will be

Mohan buys a watch for $Rs. 350$ and sells it for $Rs. 392$. Find out his percentage of profit.

$A$ sold a pen to $B$ at a profit of $20\%,$ $B$ sold the same pen to $C$ for $Rs.\,75$ thereby making a profit of $25 \% .$ Find the price at which $A$ bought the pen? (in $Rs.$)

Peter purchased a machine for $Rs. 80000$ and spent $Rs. 5000$ on repairs and $Rs. 1000$ on transport,then sold it with a $25\%$ profit. At what price did he sell the machine? (in $Rs$)