Answer
$\$70$
Work Step by Step
Let
x = number of half-dollars
y = number of quarters
Note that:
half-dollar = $\$0.50$
a quarter = $\$0.25$
Thus, the monetary value of the coins will be represented by:
monetary value = $0.50x + 0.25y$
Since $x=40$ and $y=200$, then the monetary value of the coins is:
$=\$0.50(40) + \$0.25(200)
\\=\$20 + \$50
\\=\$70$