Arora, Selango, etc....
This problem/discussion should be flagged for all prospective gmat takers!
So much of this test is about reading carefully and finding what the trick is in the problem. Every time I go through an official GMAT Prep Test with one of my students I am struck by how many of the quant problems have less to do with high level quant skills and more to do with reading skills and general problem solving.
I have just started participating on this forum (though have been teaching the GMAT for 7+ years) and noticed immediately what incredible resources you both are to this site. Also, both of you clearly have HIGH level quant skills so it means something if both of you make a mistake on the same problem! We are all going to make these types of mistakes (God knows I make plenty) but the key is to learn from them every single time.
This problem in particular is great because it is using what I often call the double trap! In most tricky median problems, people forget that if the median is say 30 in a set of 13 numbers that the first 7 could all be 30 or the last 7 could all be 30. Having seen that type of trick before it is easy to quickly apply the same thinking here without noticing that all the integers must be different. One thing is for sure with these test makers: as soon as they establish a pattern with a certain trap or trick they will then turn it around and trap people who think it is the same problem!
The point that I try to make with my students is that you must actively look for tricks and subtleties in reading EVERY time you solve a quant problem. Before hitting next, make sure that you have not misinterpreted the wording and if the problem came together too nicely you are probably making a mistake. I have a collection of what I call "read carefully" problems that are so important and will link to a few of my favorites at the end.
Brian, my colleague at Veritas, has emphasized in many superb posts that this test is trying to determine who is best suited for business school not who has the highest level quant skills. To accomplish this goal, the test makers specifically make questions that test the following:
1. Problem Solving
2. Reading Skills
3. Logic
4. Ability to Perform under Pressure
5. Knowledge and Understanding of Basic Quant and Grammar Skills through mid high school.
Remember to engage all aspects of your brain on every quant problem, not just your knowledge of mathematics, and it will make that difference between a 48/49 and 50/51!
My two favorite examples of these types of questions are the following:
1. This question has been discussed many times on this forum and I honestly have only seen a few people get it correct the first time that they saw it. Several students of mine who went on to score 99th percentile on the quant did not get this right.
https://www.beatthegmat.com/gmat-prep-t62358.html#283687 Note that in this link the answer choices are not in boxes as they are supposed to be.
2. This seemingly simple problem is all about reading comp and most people misinterpret how the fines are supposed to be calculated.
https://www.beatthegmat.com/gmat-prep-si ... tml#189779
Any way - long post - but I think some important food for thought!
