An equal sum of money is invested in two schemes which

Solution

ATQ, Let the sum invested in two schemes be Rs. 'P'. Let the rate of interest be 'r%', per annum. We know that, simple interest received at the end of each year of investment is equal. Simple interest received at the end of first year = Simple interest received at the end of second year = (1800/2) = Rs. 900 Also, simple interest and compound interest received at the end of first year are equal. So, simple interest received at the end of first year = Compound interest received at the end of first year = Rs. 900 Compound interest received in the second year = 1980 - 900 = Rs. 1080 So, we can say that a sum of Rs. 900 amounts to Rs. 1080 at the end of a year at the given rate of interest. Compound interest received for 1 year = Simple interest received for 1 year Simple interest = Principal X (Rate/100) X Time 900 X (r/100) X 1 = 1080 - 900 So, r = 180 X (5/18) = 10 Therefore, rate of interest = r = 20%