What is the present value of the following future amounts? $900 to be received 8 years from now discounted back to the present at 9 percent. $400 to be received 6 years from now discounted back to the present at 7 percent. $1, 050 to be received 11 years from now discounted back to the present at 5 percent. $1, 050 to be received 4 years from now discounted back to the present at 20 percent