A new proposed investment costs $$90164$ and has installation cost of $$5815.$ The after$-$tax proceeds from selling the old investment are $$44025.$ The after$-$tax annual cashflows from the old investment are equal to $$4048,$ while the after$-$tax cashflows from the new investment are $$12171.$ Assuming both investments have an infinite useful life, what is the payback period for replacing the old investment with a new investment.