Bunuel
In a survey of office employees, 55% reported spending less than 140 minutes per day commuting, while 69% reported spending more than 90 minutes per day commuting. If 21% reported commuting exactly 90 minutes, 7% exactly 92 minutes, 7% exactly 115 minutes, 7% exactly 138 minutes, and 7% exactly 140 minutes, what is the median daily commuting time for the employees in the survey?
A. 90 minutes
B. 92 minutes
C. 115 minutes
D. 138 minutes
E. 140 minutes
GMAT Club Official Explanation:
Think of 100 employees.
69 spend more than 90 minutes, so 31 spend ≤90 minutes.
55 spend less than 140 minutes, so 45 spend ≥140 minutes.
Since 69 spend more than 90 minutes and 55 spend less than 140 minutes, (69 + 55) - 100 = 24 employees spend more than 90 minutes but less than 140 minutes: 90 minutes < (times of 24 employees) < 140 minutes.

The median would be the average of the 50th and 51st commuting times when times are arranged in ascending or descending order.
Notice that the 21 who commute exactly 90 minutes are already part of the 31 who spend 90 minutes or less, so they do not affect the top end where the median will land. Similarly, the 7 who commute exactly 140 minutes are already part of the 45 who spend 140 minutes or more, so they also do not matter.
Next, 7 exactly 92 minutes + 7 exactly 115 minutes + 7 exactly 138 minutes = 21 employees, so there are 3 employees remaining who also fall into 90 < and < 140 range.
However, 45 who spend 140 minutes or more plus 7 who spend exactly 138 minutes already account for 52 of the greatest commuting times. Even if the remaining 3 are assigned as 139 minutes, 138 minutes would still be the 50th and 51st greatest values.
Thus, the median is 138 minutes.
Answer: D.
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