An alloy is made by mixing metal $A$ costing ₹ $2000/kg$ and metal $B$ costing ₹ $400/kg$ in the ratio $A:B = 3:1$. What is the cost (in ₹) of $8$ kilograms of this alloy?

Rama mixes $20 \%$ of kerosene to his petrol and then he sells the whole mixture at the price of petrol. If the cost price of the kerosene is $40 \%$ of the $CP$ of petrol,what is the net profit percentage (in $\%$)?

$A$ mixture of $48$ litre of milk and water contains $10 \%$ of water. How much water must be added to make $20 \%$ water in the new mixture?

Find the ratio in which rice at ₹ $7.20/kg$ should be mixed with rice at ₹ $5.70/kg$ to produce a mixture worth ₹ $6.30/kg$.

The ratio of alcohol and water in $40$ $litres$ of mixture is $5:3$. Then $8$ $litres$ of the mixture is removed and replaced with water. Now,the ratio of the alcohol and water in the resultant mixture is

The average monthly salary of employees,consisting of officers and workers of an organization,is ₹$3000$. The average salary of an officer is ₹$10000$ while that of a worker is ₹$2000$ per month. If there are a total of $400$ employees in the organization,find out the number of officers and workers separately.