Percent

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Percent

by theachiever » Tue Dec 11, 2012 11:19 pm
One week a certain truck rental lot had a total of 20 trucks,all of which were on the lot Monday morning.If 50 percent of the trucks that were rented out during the week were returned to the lot on or before Saturday morning of that week,and if there were atleast 12 trucks on the lot that Saturday morning,what is the greatest number of different trucks that could have been rented out during the week?

A.18
B.16
C.12
D.8
E.4














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by puneetkhurana2000 » Wed Dec 12, 2012 12:09 am
Trucks available on Monday = 20
Rented during the week say x
Present on Saturday = Ones that are not rented + Rental Returns = (20 - x) + x/2 = 20 - x/2

As per information 20 - x/2 >= 12, so x<=16

Answer B

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by GMATGuruNY » Wed Dec 12, 2012 2:36 am
theachiever wrote:One week a certain truck rental lot had a total of 20 trucks,all of which were on the lot Monday morning.If 50 percent of the trucks that were rented out during the week were returned to the lot on or before Saturday morning of that week,and if there were atleast 12 trucks on the lot that Saturday morning,what is the greatest number of different trucks that could have been rented out during the week?

A.18
B.16
C.12
D.8
E.4
We can plug in the answers, which represent the greatest number of trucks that could have been rented.

Answer choice A: 18 rented.
Trucks left on the lot = 20-18 = 2.
Trucks that are returned = (1/2)*18 = 9.
Trucks on the lot on Saturday = 2+9 = 11.
Too few trucks are on the lot. Eliminate A.

Answer choice B: 16 rented.
Trucks left on the lot = 20-16 = 4.
Trucks that are returned = (1/2)*16 = 8.
Trucks on the lot on Saturday = 4+8 = 12.
Success!

The correct answer is B.
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by mariofelixpasku » Thu Mar 14, 2013 10:53 am
20 - R + 1/2 * R = 12 because we want to maximize R

=> B