Crane Enterprises is considering investing in a new packing machine. The new machine will provide annual cash operating inflows of $12840 for 5 years. The cost of the machine is $44040 and it can be sold at the end of its 5 -year useful life for $7000. Keltner's required rate of return is 10%. What is the packing machine's payback period? 3.43 years 6.29 years 4.46 years 7.54 years