Michael spends 3 hours cleaning his house. He spends equal amounts of time cleaning each room. If he spends one-half hour cleaning each room, how many rooms does his house have?
A. 2 rooms
B. 3 rooms
C. 5 rooms
D. 6 rooms
If Michael spends 1/2 hour cleaning each room, then he can clean two rooms in 1 hour. Therefore, he can clean his entire house in 1.5 hours. Since he spends 3 hours cleaning his house, this means that he must have 2 * 1.5 = 3 rooms.
Therefore, the answer is B. 3 rooms.