Bunuel wrote:

Last year Bakery A had total sales of cookies in December that was 4 times the average (arithmetic mean) of the monthly cookie sales totals for January through June and 3 times the average total cookie sales for July through November. The cookie sales total for December was what fraction of the total cookie sales for the year?

A. 3/14

B. 6/25

C. 1/4

D. 2/3

E. 12/19

We can let the average monthly sales of cookies for January through June = n and the average monthly sales of cookies for July through November = m; thus:

Sales in December = 4n = 3m

Furthermore, the total sales of cookies for January through June is 6n and that for July through November = 5m.

Thus, the total sales of cookies for the year is 6n + 5m + 3m = 6n + 8m.

Since 4n = 3m, n = 3m/4.

Thus, in terms of m, the total sales for the year is:

6(3m/4) + 8m = 9m/2 + 16m/2 = 25m/2.

The sales of cookies for December is 3m/(25m/2) = 3m x 2/(25m) = 6m/(25m) = 6/25 of the total sales for the year.

Answer: B

_________________

Scott Woodbury-Stewart

Founder and CEO

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