In what time will the simple interest on a certain sum be 0.24 times the principal at 12% per annum?

A bike was sold for ₹ 48,000 and a commission of ₹ 8,640 was received by the dealer. Find the rate of commission.

In how many years will a sum of money becomes three times at the rate of interest 10% per annum?

Find the amount of ₹ 30,000 from 15th January 2010 to 10th August 2010 at 12% per annum.

A person purchases electronic items worth ₹ 2,50,000. The shopkeeper charges him a sales tax of 21% instead of 12%. The consumer does not realise that he has overpaid. But after some time he finds that he has paid excess and asks the shopkeeper to return the excess money. The shopkeeper refuses and the consumer moves the consumer court. The court with due hearing orders the shopkeeper to pay the consumer the excess money paid by the way of sales tax, with an interest of 12% per annum. If the whole deliberation takes 8 months, what is the money that the consumer gets back?