



 
Maninder, Let's suppose for example that you invested rs. 640 for two years at 8% per year compounded annually. I want to write the interest rate r as a decimal fraction so r = 0.08. At the end of the first year the value of your investment is
This is the amount that you invest for the second year and hence the value of your investment at the end of the second year is
I am not going to do the arithmetic because it's the form of the expression I want you to notice. For your problem you know that this value is rs. 774.40 but you don't know the interest rate r. In the expression above replace 0.08 by r and set it equal to 774.40. Solve for r. I hope this helps,  


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