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This Question in Under 2 Minutes???

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This Question in Under 2 Minutes???

by KylieAquino87 » Fri May 23, 2014 7:25 am
Can anyone explain to me a method to do this OG problem in less than two minutes?

Many thanks!

List T consists of 30 positive decimals, none of which is an integer, and the sum of 30 decimals is S, the estimated sum of the 30 decimals E is defined as follows. each decimal in T whose tenths digit is even is rounded up to the nearest integer, each integer in decimal T whose tenth digit is odd is rounded down to the nearest integer, E is sum of resulting integers, . IF 1/3 of decimals in T have tenths digits that are even, which of follwoing is possible value of E - S ?


-16
6
10

A I only
B I and II
c I and III
D II and III
E I , II and III
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by GMATGuruNY » Fri May 23, 2014 8:14 am
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by [email protected] » Fri May 23, 2014 9:59 am
Hi KylieAquino87,

In the GMAT Quant section, not every question can be answered in under 2 minutes. Some can be answered really quickly (30 seconds), while others take longer (upwards of 3 minutes, if you know what you're doing). Holding yourself to a "2 minutes or less" standard is not realistic. The AVERAGE amount of time per Quant question is about 2 minutes, but that does not mean that you should spend 2 minutes on each question. Instead, focus on being efficient (taking notes, doing work on the pad, using tactics/pattern-matching/Number Properties in instead of doing complex math, etc.).

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Rich
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by ceilidh.erickson » Fri May 23, 2014 4:32 pm
Hi Kylie! Good to see you again.

This is certainly not a question that the GMAT expects you to do in 2 minutes. In fact, this is a question that most savvy test-takers (even those aiming for a 700+) should probably skip. The GMAT designs certain questions to be too hard to reasonably solve, primarily (as far as I can tell) for 2 reasons: 1) to bog down the stubborn students who insist on solving every problem, and 2) to make distinctions between 780 and 800 level test takers. If you're not aiming for a 780 or above, this kind of question isn't worth your time. Even if you are, it might not be!

Remember - the GMAT is above all a decision-making test, and there will be plenty of times that the best decision you can make is to skip an excruciatingly hard question.
Ceilidh Erickson
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by Brent@GMATPrepNow » Fri May 23, 2014 5:43 pm
Ceilidh makes a very good point here.

This is the kind of question that can kill a perfectionist's score, because he/she refuses to guess and move on. Remember that you can incorrectly answer questions on the GMAT and still score 800.

For more on guessing, you might like this article: https://www.beatthegmat.com/mba/2014/02/ ... n-the-gmat

Cheers,
Brent
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by [email protected] » Sat May 24, 2014 1:47 am
I may be wrong but I will guess the answer as follows :-

1/3 numbers are even and rounded UP. Therefore 2/3 numbers are rounded down.
More numbers are rounded down. So E-S should be -ve. So answer must be -16.
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