What is the difference between the compound interest on a sum of ₹10,000 at 12% p. a. for \(1{1\over4}\) years when the interest is compounded annually and when the interest is compounded 5-monthly? (nearest to a ₹)

A milkman makes 20% profit by selling milk mixed with water at Rs.9 per litre. If the cost price of 1 litre pure milk is Rs.10, then the ratio of milk and water in the said mixture is

A sum of Rs 6000 is deposited for 3 years at 5% per annum, compound interest compounded annually. The difference of interests for 3 and 2 years will be (in Rs.)

Person A can do one-fifth of the work in 3 days, while B's efficiency is half of that of A. In how many days A and B working together can do half of the work?