You are evaluating the following two projects. Use the incremental IRR to determine the range of discount rates for which each project is optimal to undertake. You should also include the range in which it does not make sense to take either project.

Year-End Cash Flows ($ thousands)

Project	0	1	2
X	-25	18	17
Y	-70	36	54

The answer is the following:

RR of X: r = .259 IRR of Y: r = .172 Incremental IRR: r = .128 Take Y over X when cost of capital is below 12.8%, Take X when cost of capital is between 12.8% and 25.9%, and neither project should be taken if cost of capital is over 25.9%

Please show work via formulas and the like to reach the answer without using excel sheet equivalents.