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Question Stats:
68% (01:50) correct
31% (00:34) wrong based on 0 sessions
GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031
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Manager
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Re: Easy probability [#permalink]
 15 Nov 2007, 15:26
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GMAT TIGER wrote: GMATT73 wrote: GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031 = 0.5^5 = close to 0.000 I make it D - 0.5 x 0.5 x 0.5 x 0.5 x 0.5 - which is 1/32 or closest to 0.31
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D .031
probability of guessing it right = .5
So probability of guessing all 5 right = (.5)*(.5)*(.5)*(.5)*(.5) = .031
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CEO
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pretty straightforward question.
binomial prob
p(hit) = p(miss) = .5 = 1/2
(1/2)^multiplier
(1/2)^5 = 1/32 = .03xxx
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Re: Easy probability [#permalink]
21 Dec 2007, 15:39
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GMATT73 wrote: GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031
Whoops misread somethin.
1/2^5 ---> 1/32 So D.
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Re: Easy probability [#permalink]
27 Sep 2009, 02:32
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GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031
Soln: (1/2) ^ 5 = 1/32 = .031
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CEO
Status: Nothing comes easy: neither do I want.
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Re: Easy probability [#permalink]
30 Mar 2010, 07:18
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bnagdev282 wrote: whats wrong in this
P(missess none)
= 1-prob(missess all)
= 1- (1/32)
= 31/32
pls explain thks You should have use this if they had asked he atleast got 1 right then that P = 1-( P( no right) ) here it is asked he doesnt miss all you have skipped the case when he missed 1,2,3,4 questions wrong. p(1) = 1/2 p2 = 1/4 p3 = 1/8 p4 = 1/16 now subtract p1+p2+p3+p4 = 0.9375 from 31/32=0.96875 you will get p =0.03125 Hence D..... Do not down the cases you didnt considered . Hope this helps.
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Re: Easy probability [#permalink]
15 Nov 2007, 15:35
alrussell wrote: GMAT TIGER wrote: GMATT73 wrote: GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031 = 0.5^5 = close to 0.000 I make it D - 0.5 x 0.5 x 0.5 x 0.5 x 0.5 - which is 1/32 or closest to 0.31 yup yup agree with D. 0.031.
thought 0.5 to the power 5 would result in negligible value close to 0.
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Current Student
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Answer is naturally D. Guess I had better study instead!
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Director
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Re: Easy probability [#permalink]
21 Dec 2007, 20:00
GMATT73 wrote: GMATT randomly guesses the answers to a five-question true/false section on his stats final. If there is a 0.50 probability of making the correct choice on each question, then the probability that GMATT misses no questions is:
A) 0.000
B) 0.200
C) 0.500
D) 0.031
=0.5*0.5*0.5*0.5*0.5
=0.03125
Answer is D
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Director
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Re: Easy probability [#permalink]
24 Jul 2009, 19:15
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Re: Easy probability [#permalink]
04 Mar 2010, 04:47
It´s great to work through this questions with all of you guys! It feels almost like a group work 
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Intern
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Re: Easy probability [#permalink]
30 Mar 2010, 03:48
whats wrong in this
P(missess none)
= 1-prob(missess all)
= 1- (1/32)
= 31/32
pls explain thks
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Manager
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Re: Easy probability [#permalink]
18 Jun 2011, 07:03
0.5^5 = 1/32 = 0.031 ans D
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Re: Easy probability [#permalink]
28 Nov 2011, 09:08
Pro = (1/2)^5 = .031
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Re: Easy probability
[#permalink]
28 Nov 2011, 09:08
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