BTGmoderatorLU wrote:Source: GMAT Prep
A certain list consists of five different integers. Is the average (arithmetic mean) of the two greatest integers in the list greater than 70 ?
1) The median of the integers in the list is 70.
2) The average of the integers in the list is 70.
The OA is D
The key to this question is five
different integers.
Since there are
5, odd numbers of
different integers, the median of the integers would be the third-largest integer. The 1st and the 2nd integer must be less than the median and the 4th and the 5th integer must be greater than the median.
Thus, if the median is greater than or equal to 69, the minimum value of the 4th integer = 70 and the minimum value of the 5th integer = 71, making the average of the two greatest integers greater than 70 (< 70.5).
Let's take each statement one by one.
1) The median of the integers in the list is 70.
As discussed above, the minimum value of the 4th integer = 71 and the minimum value of the 5th integer = 72, making the average of the two greatest integers greater than 70 (< 71.5). Sufficient
2) The average of the integers in the list is 70.
Since the average = 70, the sum of five different integers = 70*5 = 350. In order to minimize the values of 4th and the 5th integer 71 and 72; the five integers must be: 68, 69, 70, 71 and 72, making the average of the two greatest integers greater than 70 (< 71.5). Sufficient
The correct answer:
D
Hope this helps!
-Jay
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