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m14#15

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m14#15 [#permalink] New post 31 Jan 2011, 09:04
The average weight of 15 items is 8 kg. The least average weight of 5 items of these 15 is 5 kg. If no item weighs less than 5 kg, what is the maximum number of items that can have the same weight?

(C) 2008 GMAT Club - m14#15

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* 5
* 6
* 10
* 14

15 items cannot have the same weight. It would contradict the statement that the least average weight of 5 items is 5 kg. But 14 items can have the same weight of 5 kg. The 15th item will have to weigh 50 kg to make the average weight equal 8 kg.
The correct answer is E.

Hello, can somebody elaborate on this problem ?
THANK YOU
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Re: m14#15 [#permalink] New post 31 Jan 2011, 09:15
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tinki wrote:
The average weight of 15 items is 8 kg. The least average weight of 5 items of these 15 is 5 kg. If no item weighs less than 5 kg, what is the maximum number of items that can have the same weight?

(C) 2008 GMAT Club - m14#15

* 3
* 5
* 6
* 10
* 14

15 items cannot have the same weight. It would contradict the statement that the least average weight of 5 items is 5 kg. But 14 items can have the same weight of 5 kg. The 15th item will have to weigh 50 kg to make the average weight equal 8 kg.
The correct answer is E.

Hello, can somebody elaborate on this problem ?
THANK YOU


Total weight of these 15 items is 15*8=120 kg.

Now, as average weight of 5 items out of 15 is 5 kg. and as no item weighs less than 5 kg, then each of these 5 lightest items weight exactly 5kg.

But there might be more than 5 items with weight of 5kg. Why not 14? 14*5=70 and in this case the the las item will be 50 kg to make the average wight of 8kg (70+50=120).

Answer: E.

Hope it's clear.
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Re: m14#15 [#permalink] New post 31 Jan 2011, 09:56
go that. many many thanks 4 your swift responses :)
Re: m14#15   [#permalink] 31 Jan 2011, 09:56
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