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?