If the cost price of $20$ articles is equal to the selling price of $15$ articles, find the profit percent?

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 tradesman gives $4 \%$ discount on the marked price and gives one article free for buying every $15$ articles and thus gains $35 \% .$ The marked price is appox. how much percent above the $CP$?

Two toys are sold at $Rs.\,504$ each. One toy brings the dealer a gain of $12 \%$ and the other a loss of $4 \%$. The gain or loss per cent by selling both the toys is

The percentage profit earned by selling an article for $Rs.\,1920$ is equal to the percentage loss incurred by selling the same article for $Rs.\,1280.$ At what price should the article be sold to make $25 \%$ profit? (in $Rs.$)

Selling price of a glass is $Rs.\, 1965$ and loss per cent is $25 \%$. If selling price is $Rs.\,3013,$ then what will be the profit percent?