GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 13 Dec 2019, 21:37

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

What is the probability that Lee will make exactly 5 errors on a certa

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59721
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 04 Aug 2018, 09:42
2
22
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

72% (01:01) correct 28% (01:08) wrong based on 537 sessions

HideShow timer Statistics

What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.



NEW question from GMAT® Quantitative Review 2019


(DS06810)

_________________
Most Helpful Community Reply
Retired Moderator
User avatar
D
Joined: 30 Jan 2015
Posts: 789
Location: India
Concentration: Operations, Marketing
GPA: 3.5
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post Updated on: 04 Aug 2018, 13:29
7
6
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?


(1) The probability that Lee will make 5 or more errors on the test is 0.27.
Exactly 5 errors + More than 5 errors = 0.27
No information about fewer than 5 errors
Insufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.
Fewer than 5 errors + Exactly 5 errors = 0.85
No information about More than 5 errors
Insufficient

Combining both :
(=> 5 errors) + (=< 5 errors)
= 0.27 + 0.85
= 1.12
Now, notice how a probability can not be more than 1, so the extra value obtained i.e 0.12 must be that of the exact 5 errors.
Therefore, 1.12 - 1 = 0.12
Sufficient

Hence, C.
_________________
The few, the fearless !

Thanks :-)

Originally posted by sudarshan22 on 04 Aug 2018, 11:10.
Last edited by sudarshan22 on 04 Aug 2018, 13:29, edited 1 time in total.
General Discussion
Senior Manager
Senior Manager
User avatar
D
Joined: 18 Jun 2018
Posts: 255
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 04 Aug 2018, 11:23
4
2
sudarshan22 wrote:
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?


(1) The probability that Lee will make 5 or more errors on the test is 0.27.
Exactly 5 errors + More than 5 errors = 0.27
No information about fewer than 5 errors
Insufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.
Fewer than 5 errors + Exactly 5 errors = 0.85
No information about More than 5 errors
Insufficient

Combining both :
(=> 5 errors) + (=< 5 errors)
= 0.27 + 0.85
= 1.12
Now, notice how a probability can not be more than 1, so the extra value obtained i.e 0.12 must be that of the exact 5 errors.
And since the probability of exact 5 errors is added twice while combining both statements(once from each statement), half of the extra value obtained must be the probability of exactly 5 errors on a certain typing test

Therefore, 1.12 - 1 = 0.12
Half of 0.12 = 0.06
Sufficient


Hence, C.

sudarshan22
Just small correction

P(5)+P(6)+............+P(n) = 0.27 ......Statement 1
P(0)+P(1)+ P(2)+........+P(5) = 0.85...Statement 2
Adding statement 1 and statement 2
[P(0)+P(1)................+P(5)+...........+P(n)] + P(5) = 0.27+0.85
1 +P(5) = 1.12
P(5)= 1.12-1 =0.12
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9876
Location: Pune, India
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 07 Oct 2018, 07:48
3
1
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.



NEW question from GMAT® Quantitative Review 2019


(DS06810)



We know that

1 = P (Fewer than 5 errors) + P (Exactly 5 errors) + P (More than 5 errors) ....... (I)

(1) The probability that Lee will make 5 or more errors on the test is 0.27.

P (Exactly 5 errors) + P (More than 5 errors) = 0.27
Putting this in (I) we can get the value of P (Fewer than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.

P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.85
Putting this in (I) we can get the value of P (More than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

Using both,
P (Exactly 5 errors) + P (More than 5 errors) + P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.27 + 0.85
P (Exactly 5 errors) + 1 = 1.12
P (Exactly 5 errors) = 0.12
Sufficient

Answer (C)
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Director
Director
User avatar
D
Status: Learning stage
Joined: 01 Oct 2017
Posts: 990
WE: Supply Chain Management (Energy and Utilities)
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 04 Aug 2018, 13:23
2
1
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.

NEW question from GMAT® Quantitative Review 2019


(DS06810)


Let P(A)=Probability that Lee will make 5 or more errors on the test.
P(B)=Probability that Lee will make 5 or fewer errors on the test.
We have, P(A or B)=P(A)+P(B)-P(A and B)------------(1)

Question stem:- Probability that Lee will make exactly 5 errors on a certain typing test=P(A and B)=?
From (1), we have P(A and B)=P(A)+P(B)-P(A or B)---------------(2)

St1:- The probability that Lee will make 5 or more errors on the test is 0.27.
Or, P(A)=0.27.
We can't determine P(A and B).
Insufficient.

St2:- The probability that Lee will make 5 or more errors on the test is 0.27.
Or, P(B)=0.85.
We can't determine P(A and B).
Insufficient.

Combining, we have P(A or B)=1 [Lee makes at least 5 errors or at most 5 errors]
P(A and B)=P(A)+P(B)-P(A or B)
Or, P(A and B)=0.27+0.85-1=1.12-1=0.12
Sufficient.

Ans. (C)
_________________
Regards,

PKN

Rise above the storm, you will find the sunshine
Senior Manager
Senior Manager
avatar
G
Joined: 10 Jan 2013
Posts: 309
Location: India
Concentration: General Management, Strategy
GPA: 3.95
GMAT ToolKit User Premium Member Reviews Badge
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 05 Aug 2018, 05:39
1
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.

NEW question from GMAT® Quantitative Review 2019


(DS06810)


A good question.

a. prob of 5 errors + prob of more than 5 errors = .27 ---> NS

b. prob of 5 errors + prob of less than 5 errrors= .85 ---> NS

both of them individually give no idea of exactly 5 errors..

we get 2 equations on combining both so C
Retired Moderator
User avatar
D
Joined: 30 Jan 2015
Posts: 789
Location: India
Concentration: Operations, Marketing
GPA: 3.5
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 04 Aug 2018, 11:43
Bismarck wrote:
Just small correction

P(5)+P(6)+............+P(n) = 0.27 ......Statement 1
P(0)+P(1)+ P(2)+........+P(5) = 0.85...Statement 2
Adding statement 1 and statement 2
[P(0)+P(1)................+P(5)+...........+P(n)] + P(5) = 0.27+0.85
1 +P(5) = 1.12
P(5)= 1.12-1 =0.12


Bismarck
Ohh yes, that makes much sense. I was just plugging and chugging and what not to solve the question.
Glad it was just a DS question(exact value is not required), and not a PS question.

Thanks much for rectifying the blunder . :thumbup:
_________________
The few, the fearless !

Thanks :-)
Manager
Manager
avatar
B
Joined: 10 Sep 2014
Posts: 75
Location: Bangladesh
GPA: 3.5
WE: Project Management (Manufacturing)
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 06 Oct 2018, 11:57
Bunuel, VeritasKarishma ScottTargetTestPrep please share your approach to this problem. Thanks.
Intern
Intern
avatar
B
Joined: 09 Sep 2019
Posts: 2
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 16 Sep 2019, 15:14
Why is it not 0.06 as the probability, when you add the equations you get 2P(5) + P(>5) + P(<5) =1.12 ?
Manager
Manager
avatar
B
Joined: 31 Mar 2019
Posts: 58
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 05 Nov 2019, 10:13
sambank1 wrote:
Why is it not 0.06 as the probability, when you add the equations you get 2P(5) + P(>5) + P(<5) =1.12 ?



Correct , even I am also thinking the same , as P(Exact 5 ) is added twice so it should be 0.12/2 = 0.06

Pls help

Posted from my mobile device
Manager
Manager
avatar
B
Joined: 31 Mar 2019
Posts: 58
What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 05 Nov 2019, 10:19
VeritasKarishma wrote:
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.



NEW question from GMAT® Quantitative Review 2019


(DS06810)



We know that

1 = P (Fewer than 5 errors) + P (Exactly 5 errors) + P (More than 5 errors) ....... (I)

(1) The probability that Lee will make 5 or more errors on the test is 0.27.

P (Exactly 5 errors) + P (More than 5 errors) = 0.27
Putting this in (I) we can get the value of P (Fewer than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.

P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.85
Putting this in (I) we can get the value of P (More than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

Using both,
P (Exactly 5 errors) + P (More than 5 errors) + P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.27 + 0.85
P (Exactly 5 errors) + 1 = 1.12
P (Exactly 5 errors) = 0.12
Sufficient

Answer (C)



Hi karishma ,

Could you please explain why P(Exact 5) is not 0.12/2 = 0.06 as it is added twice VeritasKarishma

Posted from my mobile device
Manager
Manager
avatar
B
Joined: 31 Mar 2019
Posts: 58
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 05 Nov 2019, 18:28
sudarshan22 wrote:
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?


(1) The probability that Lee will make 5 or more errors on the test is 0.27.
Exactly 5 errors + More than 5 errors = 0.27
No information about fewer than 5 errors
Insufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.
Fewer than 5 errors + Exactly 5 errors = 0.85
No information about More than 5 errors
Insufficient

Combining both :
(=> 5 errors) + (=< 5 errors)
= 0.27 + 0.85
= 1.12
Now, notice how a probability can not be more than 1, so the extra value obtained i.e 0.12 must be that of the exact 5 errors.
Therefore, 1.12 - 1 = 0.12
Sufficient

Hence, C.


Why the P(exact 5) is not 0.12/2 = 0.06 as it is added twice

Posted from my mobile device
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9876
Location: Pune, India
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 06 Nov 2019, 02:36
LeenaSai wrote:
VeritasKarishma wrote:
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.



NEW question from GMAT® Quantitative Review 2019


(DS06810)



We know that

1 = P (Fewer than 5 errors) + P (Exactly 5 errors) + P (More than 5 errors) ....... (I)

(1) The probability that Lee will make 5 or more errors on the test is 0.27.

P (Exactly 5 errors) + P (More than 5 errors) = 0.27
Putting this in (I) we can get the value of P (Fewer than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.

P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.85
Putting this in (I) we can get the value of P (More than 5 errors) but we cannot get the value of P (Exactly 5 errors).
Not sufficient

Using both,
P (Exactly 5 errors) + P (More than 5 errors) + P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.27 + 0.85
P (Exactly 5 errors) + 1 = 1.12
P (Exactly 5 errors) = 0.12
Sufficient

Answer (C)



Hi karishma ,

Could you please explain why P(Exact 5) is not 0.12/2 = 0.06 as it is added twice VeritasKarishma

Posted from my mobile device


Note that one P(Exactly 5 errors) is included in 1. So it is already accounted for.

1 = P (Fewer than 5 errors) + P (Exactly 5 errors) + P (More than 5 errors) ....... (I)

P (Exactly 5 errors) + P (More than 5 errors) + P (Fewer than 5 errors) + P (Exactly 5 errors) = 0.27 + 0.85
P (Exactly 5 errors) + 1 = 1.12

Hence you do not divide by 2.
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Manager
Manager
avatar
S
Joined: 10 Dec 2017
Posts: 151
Location: India
CAT Tests
Re: What is the probability that Lee will make exactly 5 errors on a certa  [#permalink]

Show Tags

New post 06 Nov 2019, 10:20
Bunuel wrote:
What is the probability that Lee will make exactly 5 errors on a certain typing test?

(1) The probability that Lee will make 5 or more errors on the test is 0.27.
(2) The probability that Lee will make 5 or fewer errors on the test is 0.85.



NEW question from GMAT® Quantitative Review 2019


(DS06810)

P(5) + P(more than 5)=0.27
P(less than 5)=1-0.27=0.73
Not sufficient
From 2
P(5)+P(less than 5)=0.85
Not sufficient
From 1 and 2
P(5)=0.85-0.73
P(5)=0.12
C:)
GMAT Club Bot
Re: What is the probability that Lee will make exactly 5 errors on a certa   [#permalink] 06 Nov 2019, 10:20
Display posts from previous: Sort by

What is the probability that Lee will make exactly 5 errors on a certa

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne