Understanding questions in multiple ways - how important?

Some OG solutions aren't exactly the most optimum. If you are happy with your method and OG has a winding solution, feel free to skip it. On the other hand, when we give multiple solutions in our books, it's because they both have merit and it is a good idea to go through both. Some questions are easily answered using one approach and others using another approach. With practice, you will know what to use where on test day (as Eli mentioned above).

You need to understand where the fourth pair is coming from so you can make an informed decision: which is more efficient, this way, or your way?

However, once you've understood it, you don't necessarily need to learn it. Once you know the OG way well enough, if you decide your way is still better, forget the OG way! Why learn a method that doesn't work as well for you?

Does that make sense?

Thanks for all your guys insight. I'll learn from it.

Here's a prime example of what I am talking about:

-Q39 OG13-

John has 10 pairs of matched socks. If he loses 7 individuals socks, what is the greatest number of pairs of matches socks he can have left?


The way I see it and got correct:

10 pairs ----> 20 socks total

20 - 7 indv. socks = 13

13 is odd and the greatest pair he can have out 13 is:

12/2 = 6 pairs.

OG Explanation:

The lowest number of pairs from 7 individuals can contain is 3 full pairs plus 1 from a fourth pair. Thus, 10-(3+1)=6

I didn't really understand where this fourth pair is coming from. However, I will learn it this way if I have to if it's worth it for future problems' sake.

You don't really 'HAVE TO' spend time on the OG solution but it is pretty straight forward too. Your solution and the OG solution are two faces of the same coin.

You can solve it in two ways: maximum how many pairs can you make from the remaining socks (you said 12/2) OR minimum how many pairs were ruined by losing 7 socks (3 pairs and 1 sock from the fourth pair so the fourth pair is also ruined).

The two solutions are complementary and you might find that knowing how to solve from two different angles adds value and gives you confidence.

In my personal opinion, I solve this question the exact same way you outlined above. The OG will sometimes have some long-algebraic way of solving problems, when in fact the question is easier to solve my using common logic. You have to train yourself to use the strategy that works for you. From what I've understood about the gmat, is that on test day, the question type are all the same, what changes are the #'s inside of the problem, and on the answer. I guess it helps to know different solutions, but if you're spending so much time reviewing one question, you're essentially wasting your studying time in reviewing 10 other questions. Learn the approach that best works for your mind, in remembering the questing type, and solution, solve then move on. This is better than reviewing one question for an hour, and being confused later about how to solve it using two or three different methods. What I do is I look at the OG guide, then compare with the MGMAT Companion guide, and compare what's easier to remember, and what my mind will absorb as easiest and fastest. You're mind will tell you choose A, or choose B, B's solution is faster, shorter, and I understand it easier. Some problems you'll notice that you'll do more work, but it will be easier to remember the steps in solving for it, opposed to some shortcut that really extracts information from the actual concept tested( that I find difficult at points), so I guess you have to choose what works for you. Hope this helps.