Answer
$\$70$
Work Step by Step
You have $40$ half-dollars and $200$ quarters.
Multiply the number of half-dollars by $0.5$ to obtain
$40 \cdot \$0.5= \$20$
Multiply the number of quarters by $0.25$ to obtain:
$200 \cdot \$0.25=\$50$
Thus, the total value of the coins is:
$\$20+\$50=\$70$