Grayson Company is considering a purchase of equipment that costs $68,000 and is expected to offer annual cash inflows of $18.000 Grayson's minimum required rate of return is 10% How many years must the cash flows last for the investment to be acceptable? ( PS1 and PVA) (Use appropriate factor(s) from the tables provided. Do not round your intermediate calculations, Round to the nearest whole year) Multiple Choice 5 years 3 years 6 years 4 years