$3-19$ An inheritance will be $$20,000.$ The interest rate for the time value of money is $7\%.$ How much is the inheritance worth now, if it will be received$$

$($a$)$ in $5$ years?$$

$($b$)$ in $10$ years?$$

$($c$)$ in $20$ years?$$

$($d$)$ in $50$ years?$$