Answer:
Payback period=2 years 5 Â months
Payback period=3 years  8 months
Explanation:
The payback period is the estimated length of time in years it takes  .
It is the number of years it takes the cash project to break-even
a) Payback period
Total cash flow for two years = 750×  2 = 1500.000
Balance of cash flow required to make up= 1800000- 1500,000 Â 300,000
Payback period = 2 years + 300,000/750,000× 12 months=  2 years 5  months
Payback period=2 years 5 Â months
b) Payback period
Total cash flow for 3 years = 450,000 + $225,000 +600,000=1,275 ,000
Balance o cash required to make up 1800,000 = 1,800,000 -1275,000= 525,000
Pay back period = 3 years + 525,000/750,000×  12 months
              = 3 years  8 months
Payback period=3 years  8 months