Stat again

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Stat again

by vinay1983 » Tue Sep 10, 2013 11:52 pm
Last year Department Store X had a sales total for December that was 4 times the average (arithmetic mean)of the monthly sales totals for January through November. The sales total for December was what fraction of the sales total for the year?

(A) 1/4
(B) 4/15
(c) 1/3
(D) 4/11
(E) 4/5

Source : OG Quant 2nd Ed OA is B
Last edited by vinay1983 on Wed Sep 11, 2013 12:20 am, edited 2 times in total.
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by [email protected] » Wed Sep 11, 2013 12:01 am
Hi vinay1983,

This is a great question to TEST values.

Let's say that for each month, January through November, the store had a sales total of 2. So, the average for those 11 months = 2

This means that December = 4(2) = 8

The question asks for the ratio of December sales to sales for the year:

December = 8
Total for the year = 8 + 11(2) = 30

Final answer:[spoiler] 8/30 = 4/15 = B[/spoiler]

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by ganeshrkamath » Wed Sep 11, 2013 11:57 pm
vinay1983 wrote:Last year Department Store X had a sales total for December that was 4 times the average (arithmetic mean)of the monthly sales totals for January through November. The sales total for December was what fraction of the sales total for the year?

(A) 1/4
(B) 4/15
(c) 1/3
(D) 4/11
(E) 4/5

Source : OG Quant 2nd Ed OA is B
Average from Jan to Nov = A
Sales in Dec = 4A

Required faction = 4A/(11A + 4A) = 4/15

Choose B

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