Please show work

Consider the following cash flow profile:

EOY	Cash Flow
0	$45,000
1	$12,000
2	$11,000
3	$10,000
4	$9,000
5	$8,000
6	$7,000
7	$6,000
8	$5,000

With a compounded annual interest rate of 6%, what single sum of money at the end of the sixth year will be equivalent to the cash flow series?

$13,725.46

Please show work for problem #90

In Problem 90, what uniform annual series over [4,7] will be equivalent to the cash flow profile if money is worth 6% compounded annually?