Last visit was: 22 Dec 2024, 10:09 It is currently 22 Dec 2024, 10:09

Close

GRE Prep 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 GRE 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.

Close

Request Expert Reply

Confirm Cancel
Verbal Expert
Joined: 18 Apr 2015
Posts: 30461
Own Kudos [?]: 36816 [5]
Given Kudos: 26100
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 30461
Own Kudos [?]: 36816 [0]
Given Kudos: 26100
Send PM
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12234 [4]
Given Kudos: 136
Send PM
Retired Moderator
Joined: 09 Jun 2020
Posts: 205
Own Kudos [?]: 235 [0]
Given Kudos: 34
GPA: 3.21
Send PM
Re: Kim has 5 pairs of shoes; each pair is a different color. If [#permalink]
no of ways in selecting 2 shoes from 10 shoes is =10c2=45ways

total no of pairs given =5

kim must choose from this 5 pairs so he will get shoes of same colour no of ways will be =5 ways

probability= 5/45 = 1/9

answer will be C

"if you like the explanation please press kudos please"
avatar
Intern
Intern
Joined: 25 Aug 2020
Posts: 9
Own Kudos [?]: 11 [0]
Given Kudos: 0
Send PM
Re: Kim has 5 pairs of shoes; each pair is a different color. If [#permalink]
A very simple solution to a seemingly difficult problem without requiring to go in depths of the permutation.
5 pair of shoes = 10 shoes
Now it doesn't matter what shoe you select first as it's inconsequential. We only have to match 2nd pair so first pair can be a shoe of any color (if that's how 5 pairs are distinguished)

Hence the first probability is selecting any of 10 shoes from the 10 shoes = 10/10 = 1

Secondly, we need to select a shoe that matches the first shoe => this can only happen in 1/9 ways (because we have 9 shoes remaining and only 1 will complete the pair)

so by chain rule = 1* 1/9 = 1/9 (answer)
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5088
Own Kudos [?]: 76 [0]
Given Kudos: 0
Send PM
Re: Kim has 5 pairs of shoes; each pair is a different color. If [#permalink]
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Prep Club for GRE Bot
Re: Kim has 5 pairs of shoes; each pair is a different color. If [#permalink]
Moderators:
GRE Instructor
88 posts
GRE Forum Moderator
37 posts
Moderator
1115 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne