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Last year Department Store X had a sales total for December
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05 Mar 2014, 02:12
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The Official Guide For GMAT® Quantitative Review, 2ND EditionLast 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 Problem Solving Question: 129 Category: Algebra; Arithmetic Applied problems; Statistics Page: 78 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you!
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Re: Last year Department Store X had a sales total for December
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SOLUTIONLast 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 Let x be the average sales per month for the first 11 months, then the total sales for the whole year would be (11 months) + (December) = 11x + 4x = 15x. (December)/(Whole year) = 4x/(15x) = 4/15. Answer: B.
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Re: Last year Department Store X had a sales total for December
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05 Mar 2014, 15:57
Lets consider each month sales as X, the december sales is 4 times the average of the other months, so december is 4X, to define what fraction of the total year sales must be fraction / total so will be 4x / 11x + 4x, 4x / 16x, and will be



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Re: Last year Department Store X had a sales total for December
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05 Mar 2014, 17:20
JanNov Avg Monthly Sales:Dec Sales 1:4 Dec Sales/(JanNov Sales Total+Dec Sales) 4/[(11*1)+(1*4)] 4/15 B
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Re: Last year Department Store X had a sales total for December
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05 Mar 2014, 21:28
Let the monthy sales, on average, be x. Monthly sales totals for January through November = 11x; Sales Total for December = 4x;
We can write the equation: 4x/(11x + 4x) = 4x/15x = 4/15;
Ans is (B)



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Re: Last year Department Store X had a sales total for December
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06 Mar 2014, 03:08
Let sales from Jan to Nov = J + F +....... +N Let sales in December = d \(Avg = \frac{(J + F +....... +N)}{11}\) \(d = 4 * \frac{(J + F +....... +N)}{11}\) \((J + F +....... +N) = \frac{11d}{4}\) ...... Sales from Jan through Nov Total sales Jan to Dec \(= \frac{11d}{4} + d = \frac{15d}{4}\) The sales total for December is \(\frac{4}{15}\) fraction of the sales total for the year Answer = B
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Re: Last year Department Store X had a sales total for December
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06 Mar 2014, 04:02
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
Sol: Let the average sale for Jan to Nov period is X then total sales in this period is 11X Now sale in Dec 4X. Total sale for JanDec: 15X Dec sale as fraction of Total sales 4X/15X or 4/15 Ans is B
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Re: Last year Department Store X had a sales total for December
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06 Mar 2014, 15:34
Plugged in numbers. Set average to 1. Total for JanNov is 11. Sales for Dec = 4. Yearly total 15. Dec = 4/15 of total.



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Re: Last year Department Store X had a sales total for December
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08 Mar 2014, 06:51
Let sum of sales from Jan to Nov=x Sales in dec=y To calculate:y/x+y We're given 4x/11=y x/y=11/4 Add 1 to both sides and reciprocate. We get 4/15 Option B.
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Re: Last year Department Store X had a sales total for December
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01 Dec 2014, 21:19
By picking:
x/11=2, 22 in eleven months
2*4=8 in December, so
8/22+8=8/30=4/15
B



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Re: Last year Department Store X had a sales total for December
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01 Dec 2014, 21:25
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Re: Last year Department Store X had a sales total for December
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16 Nov 2015, 13:23
Bunuel wrote: The Official Guide For GMAT® Quantitative Review, 2ND EditionLast 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 We can use just some smart numbers here December = 8; means that the average for each month JanNov = 2 > \(\frac{8}{8+11*2}=\frac{4}{15}\)Answer B
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Re: Last year Department Store X had a sales total for December
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25 Jul 2017, 09:45
Bunuel 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 Total sales from January to November is \(11x\) (say) Sales for December is \(4x\) Total sales of the year is \(15x\) So, the sales total for December was \(\frac{4}{15}\) part of the sales total for the year, answer will be (E)
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Re: Last year Department Store X had a sales total for December
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26 Jul 2017, 16:30
Quote: 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 We can let n = the average sales for months January through November, inclusive, and so the first eleven months’ sales = 11n and December’s sales = 4n. The sum of sales for the entire year is 11n + 4n = 15n, so December was 4n/15n = 4/15 of the sales for the year. Answer: B
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Re: Last year Department Store X had a sales total for December
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