Net present value$-$unequal lives

Dakota Mining Company has two competing proposals: a diamond core drill or a hydraulic excavator. Both pleces of equipment have an initial investment of $$900,000.$ The net cash flows estimated for the two proposals are as follows:

$\backslash$table$[[$Year$,\backslash$table$[[$Net Cash Flow$],[$Diamond Core Drill$]],\backslash$table$[[$Net Cash Flow$],[$Hydraulic Excavator$]]],[1,$$$300,000,$$$475,000$