$P$ invests $Rs.\, 9100$ for $3\, months.$ $Q$ invests $Rs.\, 6825$ for $2\, months$ and $R$ $Rs.\, 8190$ for $5\, months$ in a business. If the total profit amounts to $Rs.$ $4158,$ how much profit should $Q$ get? (in $Rs.$)

A cab driver makes a profit of $20 \%$ on every trip when he carries $3$ passengers and the price of petrol is $Rs.\,30$ a litre. Find the percentage profit for the same journey if he goes with four passengers per trip and the price of petrol reduces to $Rs.\, 24$ a litre? (in $\%$)

(Assume that revenue per passenger is the same in both the cases.)

A shopkeeper sold an article offering discount of $5 \%$ and earn a profit of $23.5 \% .$ What would have been the percentage of profit earned if no discount has been offered?

In a certain store, the profit is $320 \%$ of the cost. If the cost increases by $25 \%$ but the selling price remains constant, approximately what percentage of the selling price is the profit?

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 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