Last visit was: 24 Apr 2026, 09:46 It is currently 24 Apr 2026, 09:46
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
Back to Forum
Create Topic
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,814
Own Kudos:
811,030
 [18]
Given Kudos: 105,871
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,814
Kudos: 811,030
 [18]
Kate and her twin sister Amy want to be on the same relay-race team. 05 Jun 2019, 01:41
2
Kudos
Add Kudos
16
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

35% (medium)

Question Stats:

70% (01:39) correct 30% (02:10) wrong based on 632 sessions

History

Date
Time
Result
Not Attempted Yet
Kate and her twin sister Amy want to be on the same relay-race team. There are 6 girls in the group, and only 4 of them will be placed at random on the team. What is the probability that Kate and Amy will both be on the same team?

A. 1/5
B. 2/5
C. 3/5
D. 4/5
E. 9/10
ShowHide Answer
Official Answer
B
User avatar
LevanKhukhunashvili
User avatar
Joined: 13 Feb 2018
Last visit: 23 Jan 2021
Posts: 369
Own Kudos:
457
 [2]
Given Kudos: 50
GMAT 1: 640 Q48 V28
GMAT 1: 640 Q48 V28
Posts: 369
Kudos: 457
 [2]
Kate and her twin sister Amy want to be on the same relay-race team. 05 Jun 2019, 01:50
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Total cases: 6C4 = 15
Favorable cases 2*4C2=12

Probability: \(\frac{12}{15}=\frac{4}{5}\)

IMO
Ans: D
User avatar
sarvesh93sah
User avatar
Joined: 28 May 2017
Last visit: 03 Nov 2025
Posts: 31
Own Kudos:
28
Given Kudos: 90
Location: India
Schools: ISB'22 (WL) IIMA PGPX'22 (D) XLRI (A) IIM (A) Great Lakes (A$)
GMAT 1: 710 Q49 V38
Schools: ISB'22 (WL) IIMA PGPX'22 (D) XLRI (A) IIM (A) Great Lakes (A$)
GMAT 1: 710 Q49 V38
Posts: 31
Kudos: 28
Kate and her twin sister Amy want to be on the same relay-race team. 05 Jun 2019, 01:54
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Why have you calc for 2*4c2 instead of 4c2??

Posted from my mobile device
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 24 Apr 2026
Posts: 8,629
Own Kudos:
5,190
 [1]
Given Kudos: 243
Status:You learn more from failure than from success.
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1: 545 Q79 V79 DI73
GMAT Focus 2: 645 Q83 V82 DI81
GPA: 4
WE:Marketing (Energy)
Products:
GMAT Club Tests Forum Quiz
GMAT Focus 2: 645 Q83 V82 DI81
Posts: 8,629
Kudos: 5,190
 [1]
Kate and her twin sister Amy want to be on the same relay-race team. 05 Jun 2019, 01:55
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Kate and her twin sister Amy want to be on the same relay-race team. There are 6 girls in the group, and only 4 of them will be placed at random on the team. What is the probability that Kate and Amy will both be on the same team?

A. 1/5
B. 2/5
C. 3/5
D. 4/5
E. 9/10
Show more

let kaate and amy be considered as 1 entity
so total P = 4/5*3/4*2/3 = 2/5
IMO B
User avatar
LevanKhukhunashvili
User avatar
Joined: 13 Feb 2018
Last visit: 23 Jan 2021
Posts: 369
Own Kudos:
457
Given Kudos: 50
GMAT 1: 640 Q48 V28
GMAT 1: 640 Q48 V28
Posts: 369
Kudos: 457
Kate and her twin sister Amy want to be on the same relay-race team. 05 Jun 2019, 02:04
Kudos
Add Kudos
Bookmarks
Bookmark this Post
sarvesh93sah
Yep it's a mistake, I considered Kate, Annie and Annie,Kate as two different possibilities
User avatar
vivapopo
User avatar
Joined: 19 Jul 2017
Last visit: 06 Jun 2020
Posts: 32
Own Kudos:
6
Given Kudos: 1,158
Posts: 32
Kudos: 6
Kate and her twin sister Amy want to be on the same relay-race team. 06 Dec 2019, 12:09
Kudos
Add Kudos
Bookmarks
Bookmark this Post
sarvesh93sah
Why have you calc for 2*4c2 instead of 4c2??

Posted from my mobile device
Show more
BECAUSE BOTH
User avatar
LeenaSai
User avatar
Joined: 31 Mar 2019
Last visit: 11 Nov 2021
Posts: 87
Own Kudos:
102
 [1]
Given Kudos: 105
Posts: 87
Kudos: 102
 [1]
Kate and her twin sister Amy want to be on the same relay-race team. 21 Aug 2020, 20:47
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Archit3110
Bunuel
Kate and her twin sister Amy want to be on the same relay-race team. There are 6 girls in the group, and only 4 of them will be placed at random on the team. What is the probability that Kate and Amy will both be on the same team?

A. 1/5
B. 2/5
C. 3/5
D. 4/5
E. 9/10

let kaate and amy be considered as 1 entity
so total P = 4/5*3/4*2/3 = 2/5
IMO B
Show more

Can you explain your approach please

Posted from my mobile device
User avatar
MikeScarn
User avatar
Current Student
Joined: 04 Sep 2017
Last visit: 25 Jan 2026
Posts: 263
Own Kudos:
1,301
 [2]
Given Kudos: 227
Location: United States (IL)
Concentration: Technology, Leadership
Schools: Tuck '24 (WA) Harvard '24 (D) Kellogg '24 (WA) Wharton '24 (D) Haas '24 (D) Sloan '24 (D) Fuqua '24 (D) Booth '24 (M) Yale '24 (A$)
GMAT 1: 690 Q44 V41
GMAT 2: 730 Q50 V38
GPA: 3.62
WE:Sales (Computer Software)
Schools: Tuck '24 (WA) Harvard '24 (D) Kellogg '24 (WA) Wharton '24 (D) Haas '24 (D) Sloan '24 (D) Fuqua '24 (D) Booth '24 (M) Yale '24 (A$)
GMAT 2: 730 Q50 V38
Posts: 263
Kudos: 1,301
 [2]
Kate and her twin sister Amy want to be on the same relay-race team. 18 Sep 2020, 06:12
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
\(\frac{4C2}{6C4}\) = \(\frac{6}{15}\) = \(\frac{2}{5}\)

Total Combinations = 6C4 = 15

Total Favorable Outcomes = 4C2 = 6
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,973
Own Kudos:
1,117
Posts: 38,973
Kudos: 1,117
Kate and her twin sister Amy want to be on the same relay-race team. 02 Aug 2025, 12:46
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109814 posts
Krunaal
Tuck School Moderator
853 posts