Last visit was: 22 Apr 2026, 20:35 It is currently 22 Apr 2026, 20:35
Home
Messages
Tests
Schools
Events
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
User avatar
briozeal
User avatar
Joined: 10 Oct 2005
Last visit: 23 Aug 2007
Posts: 34
Own Kudos:
14
Posts: 34
Kudos: 14
Kate and Danny each have $10. Together, they flip a fair 12 Feb 2007, 21:20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
N
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

History

Date
Time
Result
Not Attempted Yet
Kate and Danny each have $10. Together, they flip a fair coin 5 times. Every time the coin lands on heads, Kate gives Danny $1. Every time the coin lands on tails, Danny gives Kate $1. After the five coin flips, What is the probability that Kate has more than $10 but less than $15 ?

OA will follow !



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
ggarr
User avatar
Joined: 12 Jun 2006
Last visit: 20 Mar 2010
Posts: 263
Own Kudos:
842
Given Kudos: 1
Posts: 263
Kudos: 842
Kate and Danny each have $10. Together, they flip a fair 12 Feb 2007, 22:16
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Quote:
Kate and Danny each have $10. Together, they flip a fair coin 5 times. Every time the coin lands on heads, Kate gives Danny $1. Every time the coin lands on tails, Danny gives Kate $1. After the five coin flips, What is the probability that Kate has more than $10 but less than $15 ?
Show more
Given the above, Kate can only win either 11 or 13 dollars. Therefore, she needs to win either 3 or 4 flips:

5C3 = 10
5C4 = 5

There are a total of 32 different outcomes:
TTTTT
FFFFF
5C1
5C2
5C3
5C4

Probability of the above happening is 15/32
User avatar
briozeal
User avatar
Joined: 10 Oct 2005
Last visit: 23 Aug 2007
Posts: 34
Own Kudos:
14
Posts: 34
Kudos: 14
Kate and Danny each have $10. Together, they flip a fair 13 Feb 2007, 05:51
Kudos
Add Kudos
Bookmarks
Bookmark this Post
OA is 15/32.

Thanks dude for the explaination !
User avatar
prude_sb
User avatar
Joined: 12 Mar 2006
Last visit: 13 Jul 2020
Posts: 189
Own Kudos:
264
Given Kudos: 3
Concentration: Management, Strategy & Finance
Schools:Kellogg School of Management
Posts: 189
Kudos: 264
Kate and Danny each have $10. Together, they flip a fair 13 Feb 2007, 23:12
Kudos
Add Kudos
Bookmarks
Bookmark this Post
briozeal
Kate and Danny each have $10. Together, they flip a fair coin 5 times. Every time the coin lands on heads, Kate gives Danny $1. Every time the coin lands on tails, Danny gives Kate $1. After the five coin flips, What is the probability that Kate has more than $10 but less than $15 ?

OA will follow !
Show more


problem = probability of having 1 to 4 tails

5C1(1/32) + 5C2(1/32)...5C4(1/32)

(1/32)*(5 + 5*4/2 + 5*4*3/6 + 5) = 30/32 = 15/16
User avatar
prude_sb
User avatar
Joined: 12 Mar 2006
Last visit: 13 Jul 2020
Posts: 189
Own Kudos:
264
Given Kudos: 3
Concentration: Management, Strategy & Finance
Schools:Kellogg School of Management
Posts: 189
Kudos: 264
Kate and Danny each have $10. Together, they flip a fair 13 Feb 2007, 23:15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ggarr
Quote:
Kate and Danny each have $10. Together, they flip a fair coin 5 times. Every time the coin lands on heads, Kate gives Danny $1. Every time the coin lands on tails, Danny gives Kate $1. After the five coin flips, What is the probability that Kate has more than $10 but less than $15 ?
Given the above, Kate can only win either 11 or 13 dollars. Therefore, she needs to win either 3 or 4 flips:

5C3 = 10
5C4 = 5

There are a total of 32 different outcomes:
TTTTT
FFFFF
5C1
5C2
5C3
5C4

Probability of the above happening is 15/32
Show more



hah ! silly of me ... 5C1 & 5C2 dont qualify ! thank you
User avatar
adub35
User avatar
Joined: 29 Nov 2006
Last visit: 28 Mar 2008
Posts: 55
Own Kudos:
257
Posts: 55
Kudos: 257
Kate and Danny each have $10. Together, they flip a fair 14 Feb 2007, 09:50
Kudos
Add Kudos
Bookmarks
Bookmark this Post
where does it say that Kate has to win? 15>kate>10?

1 heads--5C1
2 heads--5C2
3 heads--5C3
4 heads--5C4
User avatar
maxpowers
User avatar
Joined: 22 Feb 2004
Last visit: 23 Feb 2007
Posts: 43
Location: Florida
Posts: 43
Kudos: 0
Kate and Danny each have $10. Together, they flip a fair 14 Feb 2007, 10:31
Kudos
Add Kudos
Bookmarks
Bookmark this Post
adub35
where does it say that Kate has to win? 15>kate>10?

1 heads--5C1
2 heads--5C2
3 heads--5C3
4 heads--5C4
Show more


If one person wins, the other loses. If Katie wins once, Danny wins 4 times and Katie wins $1, but loses $4.

I did it the same way. I said that each coin flip has 2 outcomes, and there are 5 flips so its 2^5=32. I wrote out HHHTT and HHHHT as the only ways Katie can win. 3 heads is (5 c 3) and 4 heads is (5 c 4). So its (10 + 5)/32 =15/32



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!
Moderator:
Bunuel
Math Expert
109754 posts