Given the following INcremental Cash Flow for 2 alternatives, determine (a) the rate of return on the incremental cash flow, and (b) which alternative should be selected if the company's MARR is 25% per year. Alternative X3 requires the larger initial investment.

Year Incremental Cash Flow of X3 - P3 ($)

0 -2800

1-9 1100

10 2000

Seems fairly straight forward, but I keep messing up on determining the rate of return...