A trader mixes three varieties of groundnuts costing $Rs. \,50, Rs.\, 20$ and $Rs.\, 30$ per $k g$ in the ratio $2: 4: 3$ in terms of weight and sells the mixture at $Rs.\, 33$ per $kg .$ What percentage of profit does he make?

A shopkeeper sold Chairs at $Rs.\, 2139$ each after giving $7 \%$ discount on 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 chairs? (in $Rs.$)

A discount of $15 \%$ on one article is the same as a discount of $20 \%$ on another article. The costs of the two articles can be (in $Rs.$)

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 $Rs.$)

By what fraction selling price $(S.P.)$ must be multiplied to get the cost price $(C.P.)$ if the loss is $20 \% ?$