Answer:
ARR = 18.69%
Step-by-step explanation:
The accounting rate of return will be the average cash flow divide by the investment needed to generate those cash flow.

Total Cash flow
300,000 + 270,000 + 260,000 x 8 = 2,650,000
Average Cash flow:
total cash flow / life of the project
2,650,000 / 10 = 265,000
Investment = 1,418,000
265,000/1,418,000 = 0.1868829 = 18.69%
Is important to notice this rate, do not consider the time value of cash and thetime at which the cash flow are generated.