Solving $A=P{e}^n$ for $P,$ we obtain $P=A{e}^{-A}$ which is the present value of the amcunt A doe in I years il money earns interest at an annual nominal rate $r$ compounded continuously, For the function $P=20,000e^{-0\mathrm{.}05t},$ in how many years will the $$20,000$ be due in order for its present value to be $$15,000?$

In $$ years, the $$20,000$ will be due in order for its present value to be $$15,000.$

$($Type an integer or decimal rounded to the nearest hundredth as needed.$)$