Marco gives Maria $1

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

Marco gives Maria $1

by sanju09 » Sat Feb 21, 2009 4:46 am
Marco and Maria toss a coin three times. Each time a head is obtained, Marco gives Maria $1. Each time a tail is obtained, Maria gives Marco $1. What is the probability that after the 3 tosses, Marco has $1 less than he did before the 3 tosses?

Produce your own response, links :)
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

Junior | Next Rank: 30 Posts
Posts: 18
Joined: Sun Feb 15, 2009 12:04 pm

by Alpturk » Sat Feb 21, 2009 1:54 pm
probably the answer is 3/8 according to the my calculations.

Senior | Next Rank: 100 Posts
Posts: 76
Joined: Sat Jan 24, 2009 3:00 pm
Thanked: 11 times
GMAT Score:730

by BuckeyeT » Sat Feb 21, 2009 4:22 pm
3 flips, need 2 heads

Possible 2 head combinations/ total combinations =
3C2/(2^3) = 3/8.