Source: Official Guide for the GMAT 13th Ed. Problem Solving; #12 Official Guide for the GMAT 2015 14th Ed. Problem Solving; #12

2

The numbers of cars sold at a

The numbers of cars sold at a certain dealership on six of the last seven business days were 4, 7, 2, 8, 3, and 6, respectively. If the number of cars sold on the seventh business day was either 2, 4, or 5, for which of the three values does the average (arithmetic mean) number of cars sold per business day for the seven business days equal the median numbers of cars sold per day for the seven days?

3 Explanations

1

hichem elkateb

Hi ,
in Magoosh videos , to have mean equal to median , the list is either symmetric or consecutive.
so here can we avoid doing calculation and save time by just applying the rule
in this list the only possible to have mean equal to median is 5 since 5 makes the list having consecutive integers

Mar 12, 2016 • Comment

Cydney Seigerman, Magoosh Tutor

Hi Hichem,

You're totally right :) Excellent job analyzing this question!

Mar 13, 2016 • Reply

8

Also notice that if we add [5] to the set of [2, 3, 4, 6, 7, 8], the result is a set of evenly spaced numbers. We know that if the numbers in a set are evenly spaced, then the mean and median of that set are equal.

Sep 17, 2014 • Comment

2

Gravatar Mike McGarry, Magoosh Tutor

Dec 26, 2013 • Comment

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