Answer/Step-by-step explanation:
Q=number of quarters; D=number of dimes
Q+D=30
D=30-Q . Use this to substitute for D below
$0.10D+$0.25Q=$5.85 . Substitute for D from above.
$0.10(30-Q)+$0.25Q=$5.85
$3.00-$0.10Q+$0.25Q=$5.85
$0.15Q=$2.85
Q=19
ANSWER 1: There were 19 quarters.
D=30-Q=30-19=11
ANSWER 2: There were 11 dimes.
CHECK:
$0.10D+$0.25Q=$5.85
$0.10(11)+$0.25(19)=$5.85
$1.10+$4.75=$5.85
