Grayson Company is considering a purchase of equipment that costs $51,000 and is expected to offer annual cash inflows of $14,000. Grayson's minimum required rate of return is 10%. How many years must the cash flows last for the investment to be acceptable? (PV of $1 and PVA of $1) (Use appropriate factor(s) from the tables provided. Do not round your intermediate calculations. Round to the nearest whole year.) 7:19 Multiple Choice 6 years 3 years 5 years 4 years