$A$ 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

$A$ shopkeeper sold an article offering a discount of $24 \%$ and earned a profit of $23.5 \%$. What would have been the percentage of profit earned if no discount had been offered?

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 $Rs.$)

$A, B, C$ are partners in a business. During a particular $year$,$A$ received one-third of the profit,$B$ received $\frac{1}{4}$ of the profit,and $C$ received the remaining $Rs. 5000$. How much amount of money did $A$ receive? (in $Rs.$)

On an order of $5$ dozen boxes of a consumer product,a retailer receives an extra dozen free. This is equivalent to allowing him a discount of........$\%$

$A$ man bought some fruits at the rate of $16$ for $Rs. 24$ and sold them at the rate of $8$ for $Rs. 18$. What is the profit percent (in $\%$)?