Join us for MBA Spotlight – The Top 20 MBA Fair      Schedule of Events | Register

 It is currently 05 Jun 2020, 12:17

### 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

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

# If an integer is to be randomly selected from set M above

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

### Hide Tags

Director
Joined: 22 Nov 2007
Posts: 807
If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

12 Jan 2008, 04:29
2
1
23
00:00

Difficulty:

25% (medium)

Question Stats:

70% (01:16) correct 30% (01:24) wrong based on 770 sessions

### HideShow timer Statistics

M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5
Math Expert
Joined: 02 Sep 2009
Posts: 64314
Re: M = {-6, -5, -4, -3, -2} T = {-2, -1, 0, 1, 2, 3} If an  [#permalink]

### Show Tags

31 Mar 2012, 00:34
8
4
priyalr wrote:
Hello,

I got a doubt. Any no. mulitplied by 0 is 0 and 0 is neither +ve nor -ve. Going by this prop of 0, y shld we consider 0 as one of the nos. cause any no +ve or -ve multiplied by 0 is neither positive nor negative ?

Thnx.

It's not clear what you mean by "why should we consider 0 as one of the numbers"... Anyway:

M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}
If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

In order the product of two multiples to be negative they must have different signs. Since Set M consists of only negative numbers then in order mt to be negative we should select positive number from set T, the probability of that event is 3/6=1/2, (since out of 6 number in the set 3 are positive).

Hope it's clear.
_________________
Manager
Joined: 27 Oct 2008
Posts: 128
Re: good prob  [#permalink]

### Show Tags

27 Sep 2009, 05:53
7
3
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Soln: Total number of possible ways of choosing two integers is = 5 * 6 = 30 ways
Now for the product of two integers to be chosen to be negative = they should be of opposite sign. Since set M has all negative numbers, thus we move to set T which has 3 positive numbers.
Thus total number of possible ways in which product will be negative is = 5 * 3 = 15

Probability that the product of the two integers will be negative
= 15/30
= 1/2
Ans is D
##### General Discussion
Manager
Joined: 01 Jan 2008
Posts: 176
Schools: Booth, Stern, Haas
Re: good prob  [#permalink]

### Show Tags

12 Jan 2008, 04:40
2
4
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

I think D is correct
in order to get negative integer either m should be negative and n positive
probability of m is negative =5/5=1
probability of n is positive 3/6=1/2
probability of m negative and m positive is 1*1/2=1/2
VP
Joined: 07 Nov 2007
Posts: 1068
Location: New York
Re: good prob  [#permalink]

### Show Tags

25 Aug 2008, 08:10
2
1
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

P= No of ways the product of two integers is negative/All possible values
= 5*3/5*6 =1/2
Manager
Joined: 22 Dec 2009
Posts: 225
Re: good prob  [#permalink]

### Show Tags

14 Feb 2010, 14:27
2
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Negative prod pairs = 5 x 3 = 15
total pairs possible = 5c1 x 6c1 = 5 x 6 = 30

Probability = 15 / 30 = 1/2
Manager
Joined: 01 Feb 2010
Posts: 164
Re: good prob  [#permalink]

### Show Tags

14 Feb 2010, 23:00
2
If product has to be negative then m is -ve and n is +ve or m is +ve and n is -ve. But all elements of m are -ve hence we need n to be +ve.
0 has to be excluded as any number multiplied by 0 is 0 and it is neither +ve nor -ve.

p(m&n) = p(m)*p(n) = 1*3/6 = 1/2 hence D
Intern
Joined: 01 Jul 2010
Posts: 26
Schools: LBS, Harvard, Booth, Stanford, ISB, NTU
WE 1: S/W Engineer
Re: If an integer is to be randomly selected from set M above and an integ  [#permalink]

### Show Tags

27 Aug 2010, 22:49
Total # of outcomes: 5*6= 30
# of outcomes where Product is -ve : (-6,1) ,(-6,2), (-6,3)... Hence, total: 15
Probability: 15/30 = 1/2
Manager
Joined: 26 Mar 2010
Posts: 75
Re: If an integer is to be randomly selected from set M above and an integ  [#permalink]

### Show Tags

14 Sep 2010, 01:46
udaymathapati wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}
If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?
A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Please explain where my logic is going wrong...

Required probablity=probability of selecting a -ve no from 1st set * probability of selecting a +ve no from 2st set excluding (0)

which is none o fteh choices!!! Please let me know my mistake...
Retired Moderator
Joined: 02 Sep 2010
Posts: 702
Location: London
Re: If an integer is to be randomly selected from set M above and an integ  [#permalink]

### Show Tags

14 Sep 2010, 01:48
utin wrote:
udaymathapati wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}
If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?
A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Please explain where my logic is going wrong...

Required probablity=probability of selecting a -ve no from 1st set * probability of selecting a +ve no from 2st set excluding (0)

which is none o fteh choices!!! Please let me know my mistake...

All numbers in set M are negative
Probability of selecting a negative number = 1
_________________
Intern
Joined: 03 Dec 2010
Posts: 21
Re: M = {-6, -5, -4, -3, -2} T = {-2, -1, 0, 1, 2, 3} If an  [#permalink]

### Show Tags

30 Mar 2012, 23:25
Hello,

I got a doubt. Any no. mulitplied by 0 is 0 and 0 is neither +ve nor -ve. Going by this prop of 0, y shld we consider 0 as one of the nos. cause any no +ve or -ve multiplied by 0 is neither positive nor negative ?

Thnx.
Senior Manager
Joined: 20 Aug 2015
Posts: 379
Location: India
GMAT 1: 760 Q50 V44
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

18 Oct 2015, 22:40
1
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Total number of cases = 6*6
To get a negative result, we need to multiply numbers of negative signs.
Set M has all the 6 negative numbers.
Set T has 3 positive numbers, which when multiplied by negative numbers will yield a negative number

Hence we have 6*3 favourable cases.

Probability = 18/36 = 1/2
Option D
Current Student
Joined: 24 Dec 2016
Posts: 95
Location: India
Concentration: Finance, General Management
WE: Information Technology (Computer Software)
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

14 Mar 2017, 19:07
kbulse wrote:
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

I think D is correct
in order to get negative integer either m should be negative and n positive
probability of m is negative =5/5=1
probability of n is positive 3/6=1/2
probability of m negative and m positive is 1*1/2=1/2

Set M has all negative numbers, so, the probability of selecting a negative number lies entirely on set M.
Set M has 2 negative, 1 zero and 3 positive numbers. Thus, P(negative product) = $$\frac{3}{6}$$ = $$\frac{1}{2}$$
Intern
Joined: 06 Mar 2017
Posts: 3
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

15 Mar 2017, 09:13
Shruti0805 wrote:
kbulse wrote:
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

I think D is correct
in order to get negative integer either m should be negative and n positive
probability of m is negative =5/5=1
probability of n is positive 3/6=1/2
probability of m negative and m positive is 1*1/2=1/2

Set M has all negative numbers, so, the probability of selecting a negative number lies entirely on set M.
Set M has 2 negative, 1 zero and 3 positive numbers. Thus, P(negative product) = $$\frac{3}{6}$$ = $$\frac{1}{2}$$

This question would get much more tricky if 2/3 was one of the altenatives...
Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2799
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

20 Mar 2017, 05:49
2
1
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

In order for the product of the two integers to be negative, one of them has to be negative and the other has to be positive. Since every integer in set M is negative, we must select a positive integer in set T.
Thus, the probability of selecting a negative number in set M and then a positive number in set T is:

5/5 x 3/6 = 1/2

_________________

# Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
214 Reviews

5-STAR RATED ONLINE GMAT QUANT SELF STUDY COURSE

NOW WITH GMAT VERBAL (PRE-BETA)

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Manager
Joined: 13 Dec 2013
Posts: 138
Location: United States (NY)
Concentration: General Management, International Business
Schools: Cambridge"19 (A)
GMAT 1: 710 Q46 V41
GMAT 2: 720 Q48 V40
GPA: 4
WE: Consulting (Consulting)
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

14 Apr 2017, 12:25
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

Any number picked from the first set will have the same properties (all -ve).
A positive number is required from the second set to make the product -ve. 1/2 chance of picking a +ve number from the second set.
Current Student
Joined: 21 Aug 2017
Posts: 76
Location: United States
Schools: Oxford"20 (A)
GMAT 1: 700 Q43 V42
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

05 May 2018, 11:01
This question appears to have changed in the web version...and it appears broken:

Attachment:

Screen Shot 2018-05-05 at 1.59.21 PM.png [ 38.65 KiB | Viewed 13506 times ]
BSchool Moderator
Joined: 08 Dec 2013
Posts: 777
Location: India
Concentration: Nonprofit, Sustainability
Schools: ISB
GMAT 1: 630 Q47 V30
WE: Operations (Non-Profit and Government)
Re: If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

24 May 2019, 22:59
marcodonzelli wrote:
M = {-6, -5, -4, -3, -2}
T = {-2, -1, 0, 1, 2, 3}

If an integer is to be randomly selected from set M above and an integer is to be randomly selected from set T above, what is the probability that the product of the two integers will be negative?

A. 0
B. 1/3
C. 2/5
D. 1/2
E. 3/5

total combinations-> 5C1 * 6C1
Combinations that gives us -ve value upon multiplication-> 5C1 * 3C1. [5C1 for M and 3C1 for T]

15/30, probability is 1/2. D
Intern
Joined: 30 Mar 2018
Posts: 7
If an integer is to be randomly selected from set M above  [#permalink]

### Show Tags

01 Jun 2020, 23:26
Out of interest, would any one have solved this by setting up a multiplication table on their pad? (i.e. see below)

x (-6) (-5) (-4) (-3) (-2)
(-2) + + + + +
(-1) + + + + +
(0) 0 0 0 0 0
(1) - - - - -
(2) - - - - -
(3) - - - - -

Total negative = 15
Total options = 30

--> 15/30 = 1/2
If an integer is to be randomly selected from set M above   [#permalink] 01 Jun 2020, 23:26

# If an integer is to be randomly selected from set M above

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

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