1st Day at school

  • Thread starter powergirl
  • Start date
  • #1
powergirl
It was Cheryl's first day at school. The teacher suggested that it would be a good idea for each child to meet every other child in the class. The teacher said, "When you meet, please shake hands and introduce yourself by name."

If there were 15 children in the class, how many total handshakes were there?
:uhh:
 

Answers and Replies

  • #3
powergirl
No.....Slightly wrong
 
  • #4
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
9,621
6
14.............
 
  • #5
powergirl
14...................?
 
  • #7
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
9,621
6
I thought it was only Cheryl's first day, therefore all the other children would already know each other.

If not the answer must be 210.
 
  • #8
powergirl
no.......sorry
 
  • #10
powergirl
Ya..Now it's Correct........
 
  • #11
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
9,621
6
hmm, could someone explain this one to me?

Hey dontdistrbmycircles :)
 
  • #12
powergirl
may I do that?
 
  • #13
Sure, the first boy shakes 14 hands right? Then the next shakes 13 until you get to 1, my original sum should have read [tex]\sum_{i=1}^{14}i[/tex] :P

Keeps going down one because the same person does not shake the same person's hand twice.
 
  • #14
powergirl
Ya right....
The class has 15 children. The first

child shakes hands with the other 14

children. The second child has already

shaken hands with the first child, and so

has to shake hands with only the other 13

children. In this manner, the

second-last child has to shake hands with

only one child, and the last child has

already met all the children. Thus, the

number of handshakes is

14 + 13 + ........ + 2 + 1 = 105.

If there were 15 children in the class,

then there were 105 total handshakes.
 
  • Like
Likes gracy
  • #15
Hootenanny
Staff Emeritus
Science Advisor
Gold Member
9,621
6
Damn it :grumpy:. Thanks!
 
  • #16
powergirl
Oh....Am I correct?
 

Related Threads on 1st Day at school

  • Last Post
Replies
24
Views
9K
  • Last Post
Replies
19
Views
3K
  • Last Post
Replies
16
Views
1K
Replies
3
Views
2K
  • Last Post
Replies
12
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
7
Views
2K
Replies
7
Views
977
  • Last Post
Replies
6
Views
778
Replies
32
Views
5K
Top