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

It is currently 22 Jul 2014, 06:22

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

2 numbers to be selected from 0-9. What is the p that the

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 08 Sep 2004
Posts: 6
Followers: 0

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

2 numbers to be selected from 0-9. What is the p that the [#permalink] New post 09 Sep 2004, 04:31
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
2 numbers to be selected from 0-9. What is the p that the product of two numbers is even

thanks
Director
Director
User avatar
Joined: 16 Jun 2004
Posts: 893
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Sep 2004, 04:48
1. Total no. of ways of choosing 2 numbers out of the 10 numbers = 10C2 = 45.

2. The choice of the two numbers shouldbe such that one of them have to be even and the other number can be any of the remaining numbers -so that the prod of tjhe numbers will be even.

We have 2, 4, 6, 8 as the even numbers. Selecting one among them is 4C1 ways = 4 ways.

Having selected one even number we can choose the other number from any of the remaining 9 numbers in 9C1 or 9 ways. Remember 0 is a even number.

The probability is thus (4*9)/45 = 4/5
Manager
Manager
avatar
Joined: 02 Apr 2004
Posts: 224
Location: Utrecht
Followers: 1

Kudos [?]: 6 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Sep 2004, 05:01
I have 7/9 too.

Only possibility when product is odd, when both integers are odd.
Therefore,
5/10 * 4/9 = 2/9

1 - 2/9 = 7/9

Please correct me if I am wrong.

Regards,

Alex
Intern
Intern
avatar
Joined: 08 Sep 2004
Posts: 6
Followers: 0

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

 [#permalink] New post 09 Sep 2004, 05:14
what about the posibility of getting 0. that way number is niether + or - should we not count 0 in the mix as well
so shud ans be 1- p(of 0)+p(of odd)
Manager
Manager
avatar
Joined: 02 Apr 2004
Posts: 224
Location: Utrecht
Followers: 1

Kudos [?]: 6 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Sep 2004, 05:59
From what I know, 0 is considered even.

Regards,

Alex
Manager
Manager
avatar
Joined: 16 May 2004
Posts: 65
Location: columbus
Followers: 1

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

 [#permalink] New post 09 Sep 2004, 06:00
venksune wrote:
1. Total no. of ways of choosing 2 numbers out of the 10 numbers = 10C2 = 45.

2. The choice of the two numbers shouldbe such that one of them have to be even and the other number can be any of the remaining numbers -so that the prod of tjhe numbers will be even.

We have 2, 4, 6, 8 as the even numbers. Selecting one among them is 4C1 ways = 4 ways.

Having selected one even number we can choose the other number from any of the remaining 9 numbers in 9C1 or 9 ways. Remember 0 is a even number.

The probability is thus (4*9)/45 = 4/5


couple of things venksune

first off nowhere is it mentioned that numbers cant be repeated
so I think the total number od cases is 10* 10 = 100

another thing is you considered the case where the first number of the product is even , but what about the condition where the 2nd number is even

so I think the toatl number of favourable cases are 4*9 + 9*4 = 72

so the final ans is 72/100
Your thoughts??
Manager
Manager
avatar
Joined: 02 Apr 2004
Posts: 224
Location: Utrecht
Followers: 1

Kudos [?]: 6 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Sep 2004, 07:53
Another approach:

Total integers is 10
Total even integers = 5 (0,2,4,6,8)
Total odd integers = 5 (1,3,5,7,9)
Possible selections are:

Even and Even
Even and Odd
Odd and Even
Odd and Odd

E and E:
5/10 * 4/9 = 20/90 (product is even)
E and O:
5/10 * 5/9 = 25/90 (product is even)
O and E:
5/10 * 5/9 = 25/90 (product is even)
O and O:
5/10 * 4/9 = 20/90 (product is odd)

Therefore propability of an even product is:
90/90 - 20/90 = 70/90 --> 7/9
or
20/90 + 25/90 + 25/90 = 70/90 --> 7/9

What do you guys think?
Please correct me if I am wrong.

Regards,

Alex
Director
Director
User avatar
Joined: 31 Aug 2004
Posts: 609
Followers: 2

Kudos [?]: 16 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Sep 2004, 08:53
I agree with Alex, the prob we are looking for is = 1 - prob that 2 picked numbers are both odd

=1 - 5C2/10C2 = 1-2/9= 7/9
  [#permalink] 09 Sep 2004, 08:53
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic What is the probability of selecting a clean number from a s voodoochild 5 26 Sep 2012, 10:35
If two different numbers are to be selected from set {1, 2, arjtryarjtry 9 29 Jul 2008, 09:37
If two numbers are randomly selected from set (1, 2, 3, 4, bmwhype2 1 23 Oct 2007, 11:32
What is the probability of selecting a clean number from a GMATT73 9 26 Oct 2005, 06:52
what is the probab of selecting a " clean" number from a set swath20 13 18 Feb 2005, 08:00
Display posts from previous: Sort by

2 numbers to be selected from 0-9. What is the p that the

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.