+400 Hans is staying at a hotel that has five floors, numbered $1$ through $5,$ and $10$ rooms per floor, numbered $1$ through $10.$ Hans forgets where his room is, but knows that it is on floor 3, 5, or 7, and the room number is divisible by $3.$ If Hans randomly chooses a room he knows might be his room, what is the probability that Hans chooses the correct room? Express your answer as a common fraction.
+1632 Floor 3: Room 3, 6, 9
Floor 5: Room 3, 6, 9
Floor 7: Room 3, 6, 9
9 total possible options, of which only 1 will be correct, so 1/9 (wait read below)
Also, doesn't it say that the hotel only has 5 floors, so there is no floor 7- and thus the answer could also be 1/6 if there were any typos in the question...
+1632 Floor 3: Room 3, 6, 9
Floor 5: Room 3, 6, 9
Floor 7: Room 3, 6, 9
9 total possible options, of which only 1 will be correct, so 1/9 (wait read below)
Also, doesn't it say that the hotel only has 5 floors, so there is no floor 7- and thus the answer could also be 1/6 if there were any typos in the question...
