Two rival cleaning companies charge to dust houses. Captain Dustsalot charges $20

Two rival cleaning companies charge to dust houses. Captain Dustsalot charges $20 per house call plus $ 12 per room, and Dedusters charges $30 per house call
plus $10 per room. Abigail wants to know how many rooms she must get dusted
so that Captain Dustsalot is more expensive than Dedusters. Which inequality
should she use to figure this out if x represents the number of rooms she gets
dusted?