If a shopkeeper sells $25$ articles at $Rs.\, 45$ per article after giving $10 \%$ discount and earns $50 \%$ profit. If the discount is not given the profit gained is in $\%$?

A man sells two articles, each for $Rs.\,640.$ He earns $20 \%$ profit on the first, and $40 \%$ profit on the second. Find his overall percent profit.

The marked price of a watch was $Rs.\,720.$ A man bought the same for $Rs.\, 550.80$ after getting two successive discounts, the first being $10 \% .$ The second discount rate is.......$\%$

The marked price of a piano was $Rs.\, 15,000$. At the time of sale, there were successive discounts of $20 \%$ $10 \%$ and $10 \%$ on it. The sale price was (in $Rs.$)

Ravipurchases $90$ pens and sells $40$ pens at a gain of $10 \%$ and $50$ pens at a gain of $20 \% .$ Had he sold all of them at a uniform profit of $15 \%$ he would have got $Rs.\, 40$ less. Find the cost price of each pen in $Rs.$

A trader marked the selling price of an article at $10 \%$ above the cost price. At the time of selling, he allows certain discount and suffers a loss of $1 \% .$ He allowed a discount of $\%$