even number painted on it

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

even number painted on it

by sanju09 » Wed Apr 08, 2009 5:05 am
Each of the 25 balls in a certain box is either red, blue, or white and has a number from 1 to 10 painted on it. If one ball is to be selected at random from the box, what is the probability that the ball selected will either be white or have an even number painted on it?

(1) The probability that the ball will both be white and have an even number painted on it is 0.

(2) The probability that the ball will be white minus the probability that have an eve number painted on it is 0.2.



OA E
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Data Sufficiency |

Master | Next Rank: 500 Posts
Posts: 322
Joined: Fri Mar 27, 2009 3:56 pm
Thanked: 24 times
GMAT Score:710

by mike22629 » Wed Apr 08, 2009 10:49 am
Either or Probability = p(a) + p(b) - p(a and b)

Statement I: they give you p(a and b) = 0
Know nothing about either one individually, insufficient

Statement II: they give you p(a) - p(b) = .2
Its only the difference thus, they could change.
Insuffient.

IMO E

User avatar
Master | Next Rank: 500 Posts
Posts: 246
Joined: Mon May 19, 2008 7:34 am
Location: Texaco Gas Station
Thanked: 7 times

by cubicle_bound_misfit » Wed Apr 08, 2009 2:10 pm
only one addition

p(a and b) is not equal to p(a) * p(b) as the events are not independent.

Therefore combining both statements will not help to find p(a) + p(b)
Cubicle Bound Misfit