A man borrowed a sum of Rs. 12000 from a bank at simple interest. After 3 years he paid Rs. 7000 to the bank as 1st installment and at the end of 5 years he paid Rs. 10750 as 2nd installment to clear all his dues. Find the rate percent per annum?
1
12.5%
2
15%
3
17.5%
4
20%