Last visit was: 28 Apr 2024, 09:06 It is currently 28 Apr 2024, 09:06

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
avatar
Intern
Intern
Joined: 16 Jan 2021
Posts: 5
Own Kudos [?]: 8 [2]
Given Kudos: 0
Send PM
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Own Kudos [?]: 2952 [0]
Given Kudos: 172
Location: India
WE:Education (Education)
Send PM
Senior Manager
Senior Manager
Joined: 23 Jan 2021
Posts: 294
Own Kudos [?]: 151 [0]
Given Kudos: 81
Concentration: , International Business
Send PM
Manager
Manager
Joined: 19 Feb 2021
Posts: 184
Own Kudos [?]: 173 [1]
Given Kudos: 425
GRE 1: Q170 V170
Send PM
Re: Three groups of people have 8, 6 and 10 people, respectively. How many [#permalink]
1
Let's just use different technique to calculate this problem. The total number of ways that 2 people can be selected from all the people available irrespective of the groups is 24C2. 24 because 8+6+10=24.
This is the total number of ways to select two people out of 24 people.
We have to select two people from all these groups such that they are from different groups. Instead of calculating this we can calculate that both the people chosen are form the same group and then subtract this from the total.
So to select two people from the same group we get:
8C2 + 6C2 + 10C2 here there is a plus sign because we have the or condition.
Either the two people are from the first group or the second or the third.
So our answer should be 24C2 - (8C2 + 6C2 + 10C2) = 188.
Prep Club for GRE Bot
[#permalink]
Moderators:
Moderator
1085 posts
GRE Instructor
218 posts

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