1) Which one of the following is not a prime number?

2) The banker's gain on a sum due 3 years hence at 12% per annum is Rs. 270. The banker's discount is

3) The banker's discount of a certain sum of money is Rs. 72 and the true discount on the same sum for the same time is Rs. 60. The sum due is

4) The banker's discount on a certain sum due 2 years hence is 11/10 of the true discount. The rate percent is

5) A man purchased a cow for Rs. 3000 and sold it the same day for Rs. 3600, allowing the buyer a credit of 2 years.