• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

## Difficult Math Question #33 - Probability

This topic has 4 member replies
800guy Master | Next Rank: 500 Posts
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
11

#### Difficult Math Question #33 - Probability

Mon Oct 23, 2006 2:27 pm
A number is selected at random from first 30 natural numbers. What is the probability that the number is a multiple of either 3 or 13?

(A) 17/30
(B) 2/5
(C) 7/15
(D) 4/15
(E) 11/30

800guy Master | Next Rank: 500 Posts
Joined
27 Jun 2006
Posted:
354 messages
Followed by:
5 members
11
Wed Oct 25, 2006 3:29 pm
here's the OA:
Total no from 1 to 30 = 30
total no from 1 to 30 which r multiple of 3 = 10 (eg(3,6,9,12,15,18,21,24,27,30))
total no from 1 to 30 which r multiple of 13 = 2 (eg 13,26)
P(a or b ) = p(a) + p(b)
p(a)= 10/30
p(b)=2/30
p(a) + p(b) = 10/30+2/30 = 2/5

limits660 Senior | Next Rank: 100 Posts
Joined
12 Jul 2006
Posted:
57 messages
Followed by:
2 members
Wed Oct 25, 2006 4:23 am
I believe its B

_________________
-
Jeff Sacco
www.jeffsacco.ca

rajs.kumar Senior | Next Rank: 100 Posts
Joined
09 Jun 2006
Posted:
87 messages
2
Tue Oct 24, 2006 2:49 am
2/5.

10 multiples of 3 and 2 multiples of 13 adding to a total of 12. So the probability is 12/30.

ajith Legendary Member
Joined
21 Sep 2006
Posted:
1275 messages
Followed by:
2 members
125
Test Date:
April 2010
Target GMAT Score:
740
Tue Oct 24, 2006 8:34 pm
rajs.kumar wrote:
2/5.

10 multiples of 3 and 2 multiples of 13 adding to a total of 12. So the probability is 12/30.
Agree there

### Best Conversation Starters

1 lheiannie07 80 topics
2 LUANDATO 62 topics
3 ardz24 52 topics
4 AAPL 47 topics
5 Roland2rule 43 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Jeff@TargetTestPrep

Target Test Prep

134 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

131 posts
3 GMATGuruNY

The Princeton Review Teacher

130 posts
4 Rich.C@EMPOWERgma...

EMPOWERgmat

128 posts
5 Scott@TargetTestPrep

Target Test Prep

110 posts
See More Top Beat The GMAT Experts