Answer:
1 ruler costs $0.60
Step-by-step explanation:
$20-$4.70=$15.30
Calculator =$7.50
3 Packs of Pens = $1.80 each
4 rulers= x each
$7.50 + 3($1.80) + 4x = $15.30
7.50 + 5.40 + 4x = 15.30
12.90 + 4x = 15.30
4x = 2.40
x = 0.60
