Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 26 Mar 2015, 15:45

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# 2 numbers are chosen from 0-9 inclusive, what is the

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
CEO
Joined: 15 Aug 2003
Posts: 3470
Followers: 61

Kudos [?]: 697 [0], given: 781

2 numbers are chosen from 0-9 inclusive, what is the  [#permalink]  15 Sep 2003, 06:44
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
2 numbers are chosen from 0-9 inclusive, what is the
probability that its product will be even?

Is it 7/9?

thanks
praetorian
Senior Manager
Joined: 22 May 2003
Posts: 334
Location: Uruguay
Followers: 1

Kudos [?]: 33 [0], given: 0

[#permalink]  15 Sep 2003, 20:11
I get 3/4

Number of posible pairs of numbers=C(10,2)=40

The only way we get an odd by multplying two numbers is if each of those two numbers are odd.
From 0 to 9 we have 5 odds. So the number of odd pairs is C(5,2)=10

So the answer would be 30/40
CEO
Joined: 15 Aug 2003
Posts: 3470
Followers: 61

Kudos [?]: 697 [0], given: 781

[#permalink]  15 Sep 2003, 20:20
MartinMag wrote:
I get 3/4

Number of posible pairs of numbers=C(10,2)=40

The only way we get an odd by multplying two numbers is if each of those two numbers are odd.
From 0 to 9 we have 5 odds. So the number of odd pairs is C(5,2)=10

So the answer would be 30/40

Martin,

The prob. that the first # can be odd is 5/10 and the prob that the second # is 4/9

So the prob that their product is odd = 5/10 * 4/9 = 2/9

so the prob that the product# is even = 1 - 2/9 =7/9

what did i do wrong?

thanks
praetorian
Senior Manager
Joined: 22 May 2003
Posts: 334
Location: Uruguay
Followers: 1

Kudos [?]: 33 [0], given: 0

[#permalink]  15 Sep 2003, 20:35
yours is correct

My mistake was to use Combinations instead of Arrengements(permutations)

A(10,2)=10*9=90

A(5,2)=20

It's late man
Intern
Joined: 18 Aug 2003
Posts: 14
Location: USA
Followers: 0

Kudos [?]: 0 [0], given: 0

[#permalink]  15 Sep 2003, 22:27
hold on fellows. praetorian, you are using the logic that 1 - prob that multiple is odd = prob that multiple is even rt?

thus 1 -( 5/10 X 4/9) = 7/9.

however since the number 0 is included there is a possibility that the multiple will be neither odd nor even. hence the answer cannot be 7/9.
Intern
Joined: 18 Aug 2003
Posts: 14
Location: USA
Followers: 0

Kudos [?]: 0 [0], given: 0

[#permalink]  15 Sep 2003, 23:07

wow. even though i am exremely embarrased i feel thankful that i do know that 0 is even. goes to show how a simple fact like this could have been the end of me.
Intern
Joined: 11 Jul 2003
Posts: 28
Followers: 0

Kudos [?]: 0 [0], given: 0

[#permalink]  16 Sep 2003, 10:44
1. Any number that is a multiple of 2 is even. So 0 is neither even or odd.

2. The probability that the product of 2 nos from 0-9 is even is,
(2,4,6,8) are even numbers, 4/10.

As we need to select only one number to make the product even. The selection of the second number is immaterial, because it could be even or odd.

In the approach where is the answer is 7/9, this is the answer for getting the probability of two even numbers, as 1-P(of getting to 2 even nos.)
Manager
Joined: 10 Jun 2003
Posts: 210
Location: Maryland
Followers: 2

Kudos [?]: 4 [0], given: 0

[#permalink]  16 Sep 2003, 13:14
watchdog wrote:
1. Any number that is a multiple of 2 is even. So 0 is neither even or odd.

2. The probability that the product of 2 nos from 0-9 is even is,
(2,4,6,8) are even numbers, 4/10.

As we need to select only one number to make the product even. The selection of the second number is immaterial, because it could be even or odd.

In the approach where is the answer is 7/9, this is the answer for getting the probability of two even numbers, as 1-P(of getting to 2 even nos.)

0 is even, and is neither positive nor negative.
_________________

Sept 3rd

[#permalink] 16 Sep 2003, 13:14
Similar topics Replies Last post
Similar
Topics:
15 x is the product of all even numbers from 2 to 50, inclusive 3 23 Jul 2013, 06:44
5 What is the number of integers from 1 to 1000 (inclusive) 4 16 Jan 2012, 08:56
1 What is the number of integers from 1 to 1000 (inclusive) 7 16 Nov 2007, 01:58
What is the number of integers from 1 to 1000 inclusive that 4 17 Jul 2007, 14:34
What is the probability that 2 socks chosen from 5 pairs of 4 25 Apr 2006, 10:20
Display posts from previous: Sort by

# 2 numbers are chosen from 0-9 inclusive, what is the

 Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.