By selling $90$ pens for $Rs.\, 80$ a man loses $20 \%$. What should be the selling price (in $Rs.$) of $90$ pens for $20\%$ profit?

Seema sells a pen to Sapna at a profit of $25 \% .$ Sapna sells it to Asha at a profit of $10 \%$ and Asha sells it to Kavita at a profit of $5 \%$. If Asha sells it for $Rs.\,231,$ find the cost price at which Seema bought the pen? (in $Rs.$)

A trader mixes $26\, kg$ of rice at $Rs$. $20$ per $kg$ with $30\, kg$ of rice of other variety at $Rs.\, 36$ per $kg$ and sells the mixture at $Rs.\, 30$ per $kg.$ His profit percent is

Half of $100$ articles were sold at a profit of $20 \%$ and the rest at a profit of $40 \% .$ If all of the articles had been sold at a profit of $25 \%,$ the total profit would have been $Rs.\,100$ less than earlier profit. The cost price of each article was (in $Rs.$)

A dealer buys a table listed at $Rs.\,1,500$ and gets successive discounts of $20 \%$ and $10 \% .$ He spends $Rs.\, 20$ on transportation and sells at a profit of $20 \%$ Find the selling price of the table (in $Rs.$)

A shopkeeper professes to sell his goods at cost price but uses a weight of $800\, g$ instead of kilogram weight. Thus, he makes a profit of