NEW HERE? LEARN MORE
closeclose
Last visit was: 27 Apr 2024, 21:12 It is currently 27 Apr 2024, 21:12
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

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

User avatar
kr8
Intern
Intern
Joined: 08 Sep 2004
Posts: 6
Own Kudos [?]: [0]
Given Kudos: 0
Send PM
2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 05:31
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

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

thanks



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
User avatar
venksune
Director
Director
Joined: 16 Jun 2004
Posts: 510
Own Kudos [?]: 159 [0]
Given Kudos: 0
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 05:48
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
User avatar
Alex_NL
Manager
Manager
Joined: 02 Apr 2004
Posts: 106
Own Kudos [?]: 35 [0]
Given Kudos: 0
Location: Utrecht
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 06:01
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
User avatar
kr8
Intern
Intern
Joined: 08 Sep 2004
Posts: 6
Own Kudos [?]: [0]
Given Kudos: 0
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 06:14
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)
User avatar
Alex_NL
Manager
Manager
Joined: 02 Apr 2004
Posts: 106
Own Kudos [?]: 35 [0]
Given Kudos: 0
Location: Utrecht
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 06:59
From what I know, 0 is considered even.

Regards,

Alex
User avatar
smandalika
Intern
Intern
Joined: 16 May 2004
Posts: 31
Own Kudos [?]: 4 [0]
Given Kudos: 0
Location: columbus
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 07:00
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??
User avatar
Alex_NL
Manager
Manager
Joined: 02 Apr 2004
Posts: 106
Own Kudos [?]: 35 [0]
Given Kudos: 0
Location: Utrecht
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 08:53
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
User avatar
twixt
Senior Manager
Senior Manager
Joined: 31 Aug 2004
Posts: 289
Own Kudos [?]: 344 [0]
Given Kudos: 0
Send PM
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink] New post   09 Sep 2004, 09:53
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



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Problem Solving (PS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
GMAT Club Bot
gmatclubot
Re: 2 numbers to be selected from 0-9. What is the p that the [#permalink]
09 Sep 2004, 09:53
Moderators:
Bunuel
Math Expert
92959 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions