vittalgmat wrote:On any given Saturday, flights arrive at XYZ airport every hour, for 24 hours. The average number of flights arriving at XYZ airport on any Saturday is a multiple of 12. Is the total number of flights that arrived on a Saturday > 180?
1. On the same Saturday, the median number of flight arrivals every hour is 17
2. On the same Saturday, Highest number of flight arrivals in an hour was 30.
This question seems poorly worded to me.
"The average number of flights arriving at XYZ airport on any Saturday is a multiple of 12" does NOT mean that the number of flights arriving on ANY given Saturday is a multiple of 12. So, this piece of information is completely irrelevant to this question. I'm not sure I've ever seen a DS question that contained 100% irrelevant information.
Q: is the number of flights on a Saturday > 180?
(1) Median per hour is 17. So, there are an equal number of flights/hour below 17 as above. Let's look at the extreme cases:
Maximizing # of flights: well, we could have 11 hours with 16 flights, 2 hours with 17 flights and 11 hours with a billion flights. Clearly the # of flights could be greater than 180.
Minimizing # of flights: well, we could have 11 hours with 1 flight, 2 hours with 17 flights and 11 hours with 18 flights, giving us:
11 + 34 + 198 which is > 180. So, if the median is 17, there MUST be more than 180 flights: sufficient.
(2) Highest flights/hour is 30.
Well, we could have 24 hours of 30 flights each to get a "yes" answer.
However, we could also have 1 hour of 30 flights and 23 hours of 1 flight each, giving us a total of 53 to get a "no" answer: insufficient.
(1) is sufficient alone, (2) isn't: choose (A).
