this was all the information i was given.

The owner of a number of gas stations is considering installing coffee machines in his gas stations. It will cost $260,000 to install the coffee machines, and they are expected to boost cash flows by $111,428 per year for their five-year working life. What must the cost of capital be if this investment has a profitability index of 1? 1.17% 2.34% 4.69% 5.86%