Answer: 15%
Explanation:
IRR is the discount rate that makes the NPV equal zero. Required rates of return that are less than the IRR will therefore result in a positive NPV and those that are higher will result in a negative NPV.
Use Excel to find the IRR.
= IRR(-328325,115000,115000,115000,115000)
= 15%
As the required rate of 13% is less than the IRR of 15%, the new machine will have a positive NPV.