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by jonbrazil » Mon Jun 06, 2011 3:09 pm
One night a certain motel rented 3/4 of its rooms, including 2/3 of its air conditioned rooms. If 3/5 of its rooms were air conditioned, what percent of the rooms that were not rented were air conditioned?

a. 20%
b. 33 1/3%
c. 35%
d. 40%
e. 80%

Thank you for the help!
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by MBA.Aspirant » Mon Jun 06, 2011 3:23 pm
Say total number of rooms = 400

No. of rooms rented = 3/4 * 400 = 300 (not rented = 100)

No. of rooms with AC = 3/5 * 400 = 240

No. of rooms rented with AC = 2/3 * 240 = 160

No. of rooms Not rented with AC = 240 -160 = 80

Percent of rooms not rented with AC = 80/100 = 80%

Answer is E
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by sunilramu » Mon Jun 06, 2011 4:48 pm
Say there were 60 rooms. The we can arrive at the following table using given data.

---------------------------------------
| Rented | Not Rented |Total
---------------------------------------
AC | 24 | 12 | 36
---------------------------------------
No AC | 21 | 3 | 24
---------------------------------------
Total| 45 | 15 | 60
----------------------------------------

From table above, % of non rented ac rooms = 12/15 * 100 = 80%

IMO E
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by TuanNguyen87 » Mon Jun 06, 2011 5:17 pm
Call X total rooms => rented rooms = 3X/4 => not rented rooms = X/4
Then, we have AC rooms: 3X/5 => rented rooms with AC: (2/3)*(3X/5) = 2X/5
Thus, we have not rented rooms with AC: 3X/5 - 2X/5 = X/5
As a result, (X/5)/(X/4) = 0.8 = 80%
Answer: E

Hope it's useful :D
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by jonbrazil » Mon Jun 06, 2011 6:15 pm
I understood everyone's solution! thanks!
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by cans » Mon Jun 06, 2011 8:03 pm
total rooms = n
rented=3n/4
air conditioned rooms=x=3n/5
ac rooms rented = 2x/3=2n/5
ac rooms not rented = n/5
total non-rented rooms = n/4
thus% = 80
IMO E
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by aftableo2006 » Mon Jun 06, 2011 8:27 pm
its 80% the answer is E
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by [email protected] » Fri Jun 10, 2011 4:17 am
Sum was easy but we got to try the GMAT language - what percent of the rooms that were not rented were air conditioned?

that is what is confusing....
IT IS TIME TO BEAT THE GMAT

LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!

Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
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