Answer:
You coworker is wrong.
Step-by-step explanation:
Sometimes its easier to explain with an example:
Project A Project B
Cash flow 1 50,000 100,000
Cash flow 2 50,000 100,000
Cash flow 3 100,000 100,000
Cash flow 4 100,000 25,000
Cash flow 5 100,000 25,000
total 400,000 350,000
discount rate 15% 15%
NPV 253,930 255,046
Project A's total cash flows are 14% higher than project B's, but the NPV of project B is higher, so project B should be chosen.
The main premise of finance is the value of money in time, and $1 today is worth more than $1 tomorrow. That is why the NPV is the parameter for choosing between mutually exclusive projects.