Carcass 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
An easy approach is to
assign values that satisfy the given information.
So, it could be the case that, for each month from January to November, the store made
$1 in sales.
This means the average monthly sale was
$1This means the sales total for December = (4)(
$1) =
$4So the total sales for the entire year = (11)(
$1) +
$4 =
$15$4 of the total sales of
$15 were from December.
So, the sales total for December was
4/
15 of the sales total for the year.
Answer: B