One night a certain hotel rented 2/3 of its rooms, including 2/3 of their air conditioned rooms. If 3/5 of its rooms were air conditioned, what percent of the rooms that were not rented were air conditioned?  Options:  A) 50%  B) 60%  C) 65%  D) 70%  E) 75%
The rooms which were not rented is 1/3   The AC rooms which were not rented is (1/3)*(3/5) = 1/5   The percentage of unrented rooms which were AC rooms is (1/5) / (1/3) = 3/5 = 60%   The answer is 60%.
<result>B</result>
One night a certain hotel rented 2/3 of its rooms, including 2/3 of their air conditioned rooms. If 3/5 of its rooms were air conditioned, what percent of the rooms that were not rented were air conditioned?