An investment project has the following discounted cash flows ($'000):
????????????????????? Year??????????????????????? ???????????????? ?Discount rate
????????????????????????????????????????????????????? 0%????????????????????? ?10%????????????????? ?20%
??????????????????????? 0??????????????????????????? 90? ?????????????????????? 90????????????????????? 90?
????????????????????????1???????????????????????? ?? 30???????????????????????? 27.3???????????????????? 25.0
??????????????????????? 2?????????????????????????? ??30??????????????????????? 24.8??????????????????? 29.8
?????????????????????? ?3???????????????????????????? 30??????????????????????? 22.5????? ????????????? 17.4
?????????????????????? ?4???????????????????????????? 30???????????????????????20.5?????????????????????14.5
?????????????????????????????????????????????????????? 30?????????????????????? 5.1??????????????????????(12.3)
The required rate of return on investment is 10% per annum. What is the discounted payback period of the investment project