Median - Months Problem

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Median - Months Problem

by gmatrant » Tue Oct 16, 2007 7:50 pm
Susan is looking at her cell phone bill from
the last 6 months. April’s bill was four times that
of all the other bills. If the median amount due
for a month was $32, what was the average
amount due in a month during those six months?
(A) $32
(B) $48
(C) $53
(D) $80
(E) $128

How to solve this problem? When the problem states that "he median amount due for a month was $32" - this could be for any month including April, as if we start from January, March & April form the median months. So how does one proceed with the problem?

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by jangojess » Wed Oct 17, 2007 4:54 am
this is wht i think the sol shld be....

let x be the amount due for all the 5 months except April..Now for April it will be 4x...So the avg of all the 6 months = (x*5 + 4x)/6 = 1.5x

For past 6 months the set of amount in ascending order wud be
x,x,x,x,x,4x...The median for this set wud be x itself which is given as 32. So the avg of the amount for 6 months wud be 1.5 * 32 = 48....Ans is B
Trying hard!!!

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by gmatrant » Wed Oct 17, 2007 7:09 am
jangojess wrote:this is wht i think the sol shld be....

let x be the amount due for all the 5 months except April..Now for April it will be 4x...So the avg of all the 6 months = (x*5 + 4x)/6 = 1.5x

For past 6 months the set of amount in ascending order wud be
x,x,x,x,x,4x...The median for this set wud be x itself which is given as 32. So the avg of the amount for 6 months wud be 1.5 * 32 = 48....Ans is B
"April’s bill was four times that of all the other bills"
I guess I didn't read the question properly, this clearly states that April is the last month, earlier I had confusion in finding out which was the last month..

Thanks jangojess..It just struck me when i saw your solution.