Answer:
17.9%
Explanation:
The computation of the internal rate of return of the project is shown below;
Year  0      0
Year 1 Â Â Â Â -70,000 ($10,000 - $70,000)
Year 2 Â Â Â -15,000 ($30,000 - $45,000)
Year 3 Â Â Â 115,000 ($125,000 - $10,000)
Let us assume r represent the IRR of the incremental project.
so, Â
-$70,000 ÷ (1+r) - $15,000 ÷ (1+r)^2 + $115,000 ÷ (1+r)^3 = 0
r = 17.9%