BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

A team of 2 is to be selected from a group of 5. if the number of males in the group is n, then what's the value of n?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

A team of 2 is to be selected from a group of 5. if the number of males in the group is n, then what's the value of n?

by BTGmoderatorDC » Mon Aug 23, 2021 6:40 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

A team of 2 is to be selected from a group of 5. if the number of males in the group is n, then what's the value of n?

1. The number of males in the group is one more than the number of females
2. The probability the team consists of at least one male is 9/10


OA D

Source: e-GMAT
Top
Source: — Data Sufficiency |
Legendary Member
Posts: 2499
Joined: Sun Oct 29, 2017 2:04 pm
Followed by:6 members

Re: A team of 2 is to be selected from a group of 5. if the number of males in the group is n, then what's the value of

by swerve » Tue Aug 24, 2021 5:49 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

BTGmoderatorDC wrote: ↑
Mon Aug 23, 2021 6:40 pm
 A team of 2 is to be selected from a group of 5. if the number of males in the group is n, then what's the value of n?

1. The number of males in the group is one more than the number of females
2. The probability the team consists of at least one male is 9/10


OA D

Source: e-GMAT
Let the number of males be n and the number of females be f then,
\(n+f=5\)

Statement 1.
If \(n=f+1\) then \(f+1+f=5,\) so \(f=2, n=3.\) Sufficient \(\Large{\color{green}\checkmark}\)

Statement 2:
If n males then \(f=(5-n)\) females.
Now the probability to select at least one male\(= 1-\)(prob to select all female)
\(\dfrac{1}{10}=\dfrac{(5-n)C2}{5C2}\)
\(\dfrac{1}{10}=\dfrac{(5-n)8\ast (5-n-1)}{5\ast 4}\)
\((n-5)(n-4)=2\)
\(n2-9n+18=0\)
\(n=6\) or \(3\)

But \(n=6\) not possible (as \(n+f=5\)) hence \(n=3\) and \(f=2.\) Sufficient \(\Large{\color{green}\checkmark}\)

Therefore, D
Top
Post new topic Post Reply
• Page 1 of 1