$$ How much would $$20,000$ due in $50$ years be worth today if the discount rate were $7\mathrm{.}5\%?$

$$ $$451\mathrm{.}74$

$$ $$537\mathrm{.}78$

$$ $$661\mathrm{.}47$

$$ $$656\mathrm{.}09$

$$ $$618\mathrm{.}45$