"Biggest Time Killers" - Or when to skip a question?

Forum for the GRE subject test in mathematics.
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"Biggest Time Killers" - Or when to skip a question?

Post by Legendre » Mon Aug 27, 2012 9:07 am

While doing the practice tests, I realize I have a big problem: Even on my 2nd attempt at a paper, when I knew how to solve each question and is just running through the computation, I keep running out of time! :cry:

The biggest "time killers" are those questions that I know I can solve if I spent a little bit more time on them. E.g. Spending 7-10 minutes. While wasting time on them, I keep getting the feeling that the solution was "around the corner" and refuse to give up. Also, having spent time reading the question, it feels like such a waste to let it go.

How do I know when to skip these? Spend 2 minutes per question, if I'm not rapidly approaching a solution, skip?

E.g. Those "which of the following is a metric" type question. We all know to check for triangle inequality, d(x,y) = 0 iff x = y etc. But I often get stuck thinking about how to disprove the triangle inequality for one of the options, after spending time eliminating 2-3 others.

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Joined: Tue Feb 28, 2012 12:14 am

Re: "Biggest Time Killers" - Or when to skip a question?

Post by yoyostein » Tue Aug 28, 2012 10:08 pm

Hi, I sympathise with you, as I am facing the exact same problem.

I try to divide the two hours and fifty minutes into three portions (of roughly one hour)

So, at the end of the one hour, I aim to finish around 66/3=22 questions. If I do not, I proceed to skip questions until I reach the next "set".

For metric questions, I find that the counter-example for triangle inequality often comes in the range x in (0,1). For example in Q56, 0568,

d(x,y)=(x-y)^2 is not a metric because d(0,0.5)+d(0.5,1)=1/4+1/4=1/2<d(0,1)=1

Some questions have a "short cut" that requires less time than standard methods. For example 0568,
Q1) In the xy-plane, the curve with parametric equations x =cos t and y = sin t, 0 <=t <=pi has length ?

Doing any form of integration is the slow method, the fast method is to use the formula for circumference of circle.

You can discuss on the forum, I think many people will be glad to post their "shortcuts" to the GRE problems!

You can also try guessing "D" when in doubt. (especially if you can eliminate another option that is clearly wrong) :D I have analysed the answers for GRE math subject, and find that "D" has a consistently slight higher chance of being correct.

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