P(s,g)=30g+1.10s is the cost in dollars of Paint Express's charge, where s is the space in square feet, and g is the number of gallons of paint, while:
C(s,g)=24g+1.20s is Color Creations' cost for the same space.
If P>C, when g=4:
120+1.10s>96+1.20s, 24>0.10s, 240>s, so Paint Express would charge more than Color Creations if the space was less than 240 square feet.
When s=240 their charges would be the same: 120+264=96+288=$384.
When s>240 Color Creations would charge more.