Assuming cashflows occurring in year t (Ft), and a single discount rate in decimal (r), the present value P is given by: P = St ( Ft / (1+r)t ) For example, the net present value the cashflows [20, 50, 90] discounted at a rate of 5% is: P = 20 / (1.05) + 50 / (1.05)2 + 90 / (1.05)3 = 142.14 (rounded to 2 decimal places) Assignment: Write a function NetPresentValue(flowlist, rate) that takes a list of values, and an interest rate (in decimal), and returns the net present value. The list of values is assumed to be annual flows, so for example, [10, 20] represents a flow of 10 at end of year 1, and 20 at end of year 2. Zero is a valid value, so for example, [0, 20] represents no flow at the end of year 1, and a flow of 20 at the end of year 2.