At a certain discount rate the present values of the following cash flows are equal:

(a) 808 at the end of 4 years (b) 426 at the end of 4 years plus 1000 at the end of 8 years

At the same discount rate, find the net present value of 100 deposited now, 200 deposited in 4 years and a withdrawal of 128 at the end of 8 years.