4. Discounting: For the following questions, calculate the net present value. Please show your calculations! (a) Consider the following stream of payments: Now:- $100,000 One year from now: $50,000 Two years from now: $3,000 Three years from now: $50,000 Every year forever starting four years from now: $1,000 Compute the net present value of this stream of payments, using a discount rate of (a) 4% (b) 10%