Answer:
$1.80
Explanation:
Total amount owned by Billy = $3.00
Cost of 1 bubble gum = $0.30
If Billy bought 4, the cost of 4 bubble gum = 4 * 0.30 = $1.20
Amount Billy have left = $3.00 - $1.20
Amount Billy have left = $1.80
hence the amount that billy have left is $1.80
