Answer:
3.2 years
Step-by-step explanation:
Cash payback calculates the amount of time it takes to recover the amount invested in a project from it cumulative cash flows
Amount invested = -420,000
Amount recovered in year 1 = -420,000 + 180,000 = -240,000
Amount recovered in year 2 = -240,000 + 120,000 = -120,000
Amount recovered in year 3 = -120,000 + 100,000 = -20,000
Amount recovered in year 4= - 20,000 / 90,000 = 0.22
Cash payback = 3.2 years