Answer
Hawaii has 4371 roadway miles. Delaware has 6302 roadway miles.
Work Step by Step
Let $h$ be the roadway miles in Hawaii.
The roadway miles in Delaware is $h+1931$.
$h+h+1931=10673$ $\longrightarrow$combine like terms
$2h+1931=10673$ $\longrightarrow$addition property
$2h+1931-1931=10673-1931$ $\longrightarrow$combine like terms
$2h=8742$ $\longrightarrow$multiplication property
$2h\div2=8742\div2$ $\longrightarrow$divide
$h=4371$
$h+1931=4371+1931=6302$