A shopkeeper allows a discount of $12.5 \%$ on the marked price of a certain article and makes a profit of $20 \% .$ If the article costs the shopkeeper $Rs. 210$, then the marked price of the article will be (in $Rs.$)

If a company sells a car with a marked price of $Rs$ $272000$ and gives a discount of $4 \%$ on $Rs$ $200000$ and $2.5\%$ on the remaining amount of $Rs$ $72000,$ then the actual price charged by the company for the car is (in $Rs.$)

A reduction of $21 \%$ in the price of an item enables a person to buy $3\, Kg$ more for $Rs.\,100.$ The reduced price of the item per $Kg$ is (in $Rs.$)

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

A dealer sold a bicycle at a profit of $10 \% .$ Had he brought the bicycle at $10 \%$ less price and sold it at a price $Rs.\, 60$ more, he would have gained $25 \%$. The cost price of the bicycle was

cost price of $100$ books is equal to the selling price of $60$ books. The gain or loss percentage will be