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IrinaOK
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 08:55
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A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4



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Ferihere
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 09:26
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A wild guess 1/4 but seems incorrect as it becomes too simple.

A

what is OA???
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GK_Gmat
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 09:36
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IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4
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I hate these kind of questions because they make me feel really dumb.

The light makes 3 revolutions in 60 seconds = 1 rev in 20 seconds assuming constant speed of revs.

Favorable outcome = 5 secs
Total outcome = 20 secs

Probability = 5/20 = 1/4.

Makes no sense and I have no clue how to do this. I would guess A in the exam and move the hell on!!!
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IrinaOK
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 10:27
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GK_Gmat
IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4

I hate these kind of questions because they make me feel really dumb.

The light makes 3 revolutions in 60 seconds = 1 rev in 20 seconds assuming constant speed of revs.

Favorable outcome = 5 secs
Total outcome = 20 secs

Probability = 5/20 = 1/4.

Makes no sense and I have no clue how to do this. I would guess A in the exam and move the hell on!!!
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=))

sorry about the feelings, u r not alone...
nope, AO is different I will post it later, let`s see other explanations.
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IrinaOK
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 10:29
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Ferihere
A wild guess 1/4 but seems incorrect as it becomes too simple.

A

what is OA???
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I made the same mistake. Will post OA later.
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gixxer1000
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 10:34
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GK_Gmat
IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4

I hate these kind of questions because they make me feel really dumb.

The light makes 3 revolutions in 60 seconds = 1 rev in 20 seconds assuming constant speed of revs.

Favorable outcome = 5 secs
Total outcome = 20 secs

Probability = 5/20 = 1/4.

Makes no sense and I have no clue how to do this. I would guess A in the exam and move the hell on!!!
Show more


Isn't that the probability that you are IN the light and there for the probability that you are NOT is 1 - 1/4 or 3/4

Another way of looking at it:

You are standing on the circumference of a circle. The light will cover the entire circumference in 20 seconds therefore it will only cover 25% in 5 seconds. That leaves 75% of the circumference that you could be standing on and remain in the dark.
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IrinaOK
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 11:07
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gixxer1000
GK_Gmat
IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4

I hate these kind of questions because they make me feel really dumb.

The light makes 3 revolutions in 60 seconds = 1 rev in 20 seconds assuming constant speed of revs.

Favorable outcome = 5 secs
Total outcome = 20 secs

Probability = 5/20 = 1/4.

Makes no sense and I have no clue how to do this. I would guess A in the exam and move the hell on!!!

Isn't that the probability that you are IN the light and there for the probability that you are NOT is 1 - 1/4 or 3/4

Another way of looking at it:

You are standing on the circumference of a circle. The light will cover the entire circumference in 20 seconds therefore it will only cover 25% in 5 seconds. That leaves 75% of the circumference that you could be standing on and remain in the dark.
Show more


AO is E,

thank you for your explanation, clear now.
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Vlad77
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 11:19
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IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4
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GMATClub challenges rules!!!
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beckee529
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A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4 20 Sep 2007, 15:41
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IrinaOK
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4
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yay!!! i had gotten 3/4 (E)



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!