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

Redeem

Another possibility problem

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 am
Location: India
Thanked: 375 times
Followed by:53 members

by Frankenstein » Fri Jun 24, 2011 7:56 pm
Hi,
Let the groups be g1,g2,..,g6
Each person from g1 shakes hand with each of the other 5 groups (15 men).
So, the number of hand shakes is 3*15
Now each man from g2 shakes with each of the other 4 groups(12 men) as shakes between g2 and g1 are already counted
So, the number of hand shakes is 3*12.
Similarly for g3,g4,g5,g6
So, Total number of hand shakes is 3*(15+12+9+6+3) = 3*45 = 135
(or)
Each person from each group shakes hand with each of the other groups in 15 ways.
So, 18 men shake hands in 18*15 ways.
But we are counting each hand shake twice.
So, number of hand shakes will be 18*15/2 = 135
Cheers!

Things are not what they appear to be... nor are they otherwise
Top
Post new topic Post Reply
• Page 1 of 1