math
posted by Lily .
a carpet for a small room measuring 4 ft by 7.5 ft cost $120 how much would it cost for a carpet (with the same price per square foot) for a bigger room that measures twice as long and three times as wide

cost per square foot = 120/30 = $4.00 per square foot
twice 7.5 = 15
three times 4 = 12
new area = 15(12) = 180
cost = 180(4) = $720