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If the average of 7 numbers is 72, how many of the numbers

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If the average of 7 numbers is 72, how many of the numbers [#permalink]  20 Mar 2012, 12:43
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67% (01:38) correct 32% (00:46) wrong based on 49 sessions
If the average of 7 numbers is 72, how many of the numbers are equal to 72?

(1) Of the seven numbers, six are odd integers, and the average of those integers is 72.
(2) At least one of the numbers is equal to 72.
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Re: If the average of 7 numbers is 72, how many of the numbers [#permalink]  20 Mar 2012, 12:56
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If the average of 7 numbers is 72, how many of the numbers are equal to 72?

(1) Of the seven numbers, six are odd integers, and the average of those integers is 72 --> since 6 out of 7 numbers are odd then none of them is equal to 72. Now, since the average of these 6 numbers is 72 then the 7th number must equal to 72 in order the overall average to be 72, which means that there are only one number equal to 72. Sufficient.

(2) At least one of the numbers is equal to 72. Not sufficient.

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Re: How many numbers are equivalent to 72? [#permalink]  01 Apr 2012, 10:26
1
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Clearly (A).

Statement 1: If six of the seven integers are odd and their average is 72, it follows that the last (seventh) integer has to be 72 as well. Also, as the first six integers are odd, there is just one 72 in the set. Sufficient.

Statement 2: If one or more of the numbers is 72, the remaining numbers in the set can be a combination of less, more, or equal to 72. So we can have all 72s, or some more than 72 and some less, or some more than 72, some less, and some equal to 72. This makes the number of 72s uncertain. Insufficient.

Therefore (A)
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Math Expert
Joined: 02 Sep 2009
Posts: 15147
Followers: 2536

Kudos [?]: 15645 [0], given: 1565

Re: If the average of 7 numbers is 72, how many of the numbers [#permalink]  28 May 2013, 04:29
Expert's post
Bumping for review and further discussion.
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Re: If the average of 7 numbers is 72, how many of the numbers [#permalink]  28 May 2013, 14:20
The way you guys reason it out makes it harder for me to understand
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Re: If the average of 7 numbers is 72, how many of the numbers [#permalink]  28 May 2013, 14:25
Expert's post
The way you guys reason it out makes it harder for me to understand

Can you please tell me which part was unclear to you so that to elaborate it more?
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Re: If the average of 7 numbers is 72, how many of the numbers   [#permalink] 28 May 2013, 14:25
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