A dairyman pays $Rs.\, 6.40$ per litre of milk. He adds water and sells the mixture at $Rs.\, 8$ per litre, thereby making $37.5\%$ profit. The proportion of water to milk received by the customers is

The labelled price of a cupboard is $Rs$ $6500 .$ The shopkeeper sold it by giving $5 \%$ discount on the labelled price and earned a profit of $15 \% .$ What approximately is the cost price of the cupboard? (in $Rs.$)

On an article the profit is $210 \%$ of the cost price. If the cost price increase by $40 \%$ but the selling price remains constant, approximately what percent of selling price will be the profit?

What profit/loss percent did Ravi earn if he purchased an item of $Rs.\,5600$ and sold it at $3/4$ of its cost price?

A discount series of $10 \%, 20 \%$ and $40 \%$ is equal to a single discount of.......$\%$

A shopkeeper sold two bicycles for $Rs.\,1500$ each. On one, he gains $25 \%$ and on the other he loses $20 \%$. His gain or loss per cent in the whole transaction is