A person invested Rs 20000 in a bank which is offering 10% per annum simple interest. After two years he withdrew the money from the bank and deposited the total amount in another bank which gives an interest rate of r% p.a. compounded annually. After 2 years he received an amount of Rs.2460 more than what he had invested in that bank. Find the value of r.
5
10
15
12
11