Mr. Anil wants to invest a sum of money in a scheme at a certain rate of interest for two years. He has to decide whether to invest at simple interest or compound interest. The total compound interest on the amount would be Rs. 756, whereas the total simple interest would be Rs. 720. What will be the rate if the sum is invested in such a way that simple interest becomes Rs. 900 and the total number of years is equal to the rate per annum?