Average

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Average

by sparkles3144 » Wed Jun 04, 2014 1:28 pm
The average of 11 consecutive integers is 12. Then, 9 is deducted from the first consecutive
number, 8 is deducted from the second, 7 is deducted from the third, and so on until the
last number which remains unchanged. What is the new average?

A)55
B)50
C)6
D)7.5
E)8.7

Answer E

I did this:
Total original sum = 11 * 12 = 132
Deduction = 0+ 1 + ...+ 9 = average * total numbers = 4.5 * 10 = 45
132 - 45 = 87
87/11 = 7.9 something
That option is not available.

Where did I go wrong?

Thanks!
Source: — Problem Solving |

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by [email protected] » Wed Jun 04, 2014 4:47 pm
Hi sparkles3144,

Your approach to solving this question is correct.

What is the source of this question? The presentation of this question is not "GMAT-like", the fact that the numbers are consecutive is irrelevant and the answer choices aren't presented properly. Either this question has typos (or missing information) or the source is questionable.

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by sparkles3144 » Wed Jun 04, 2014 6:24 pm
Hi Rich,

Thank you for the reply!

I got this form gmat club flashcards.
I guess I will just skip this one.

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by [email protected] » Wed Jun 04, 2014 10:59 pm
Hi sparkles3144,

I'd be suspicious of any questions that don't come from the OG books/material or a reputable source. I can't speak with any depth about the gmatclub flashcards, but if this question is indicative of those questions, then I would ignore the entire set.

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by Jim@StratusPrep » Thu Jun 05, 2014 6:54 am
I agree this wording doesn't make sense - stick with the OG...
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