This month, for the first time, we are using an official question from the new version of the GMAT as our monthly “brain teaser”. As anyone who knows the GMAT will be able to tell, it’s indistinguishable from questions that appeared on the “Classic GMAT,” but if you have not yet attempted a GMAT Focus question, now you can say that you have! This question is very doable, but like most GMAT questions, it’s tricky (and in our experience, MANY people get fooled on this one), so be careful!
In a class of 100 students, more students were born in October than in any other month. What is the least possible number of students who were born in October?
A. 8
B. 9
C. 10
D. 11
E. 12
Answer:
This is a classic Min/Max question (one in which you are asked to minimize or maximize the value of something). Test takers tend to really struggle with these types of questions, which is why they appear so often! There are many ways that one could approach this, but perhaps the easiest way is to start by realizing that 8 x 12 = 96. Most people go wrong at this point and then just add 4 more people to October. Certainly you COULD have 12 people born in October, but this question asks you what the LEAST possible number of students born in October would be! You could distribute the extra 4 people among 4 months: so you could have 9 people born in January, February, March, and October and 8 people born in all of the other months, but then October would have the same number of people as some of the other months, and this would violate the constraints of the question. However, if you simply take one of those students (say, from January) and put that person in October, that would fix the problem. October would thus have 10, two months would have 9, and the rest would have 8. So the answer is C. 10 is the least possible number of students born in October.