The rate of simple interest on a certain sum of money is 6% per annum for the first two years, 4% per annum for the next 4 years and 7% per annum for the period beyond 6 years. If the simple interest earned by a sum is rupee 3577 in 9 years. find the sum?
1
Rs.7200
2
Rs.7300
3
Rs.7000
4
Rs.7100
5
None of these