Hi All,
We're told that there are 66 people in a certain auditorium and 6 people AT MOST have birthdays in any one given month. We're asked if AT LEAST one person in the auditorium has a birthday in January. This is a YES/NO question and we can use a mix of logic and TESTing VALUES to answer it.
To start, since there are 66 people, no more than 6 have their birthdays in the same month and there are 12 months in a year, the ONLY WAY for one month to have 0 birthdays is if ALL of the other 11 months have 6 birthdays each. In that situation, there would be eleven 6s and one 0. By extension, if ANY month doesn't have 6 birthdays in it, then EVERY month would have at least one birthday in it.
1) More of the people in the auditorium have birthdays in February than in March.
Fact 1 tells us that March cannot possibly have 6 birthdays (it would have at most 5 - and that could only occur if February had 6 birthdays). Thus, since one month (in this case, March) doesn't have 6 birthdays, January will have at least 1 birthday.
Fact 1 is SUFFICIENT
2) Five of the people in the auditorium have birthdays in March.
The information in Fact 2 allows us to make the same deduction that we made in Fact 1: since one month (in this case, March) doesn't have 6 birthdays, January will have at least 1 birthday.
Fact 2 is SUFFICIENT
Final Answer: D
GMAT assassins aren't born, they're made,
Rich