A sum of money amounts to Rs. 702 in 2 years and Rs. 783 in 3 years. The rate percent is?

S.I. for 1 year = Rs. (783 - 702) = Rs 81
S.I. for 2 years = Rs. (81 x 2) = Rs. 162
∴ Sum = Rs. (702 - 162) = Rs. 540
∴ Required rate = = (100 x SI) / (P x T) = (100 x 162) / (540 x 2) % = 15%