How many handshakes were exchanged on Cheryl's first day of school?

  • Thread starter powergirl
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In summary, the teacher suggested that each child in the class should meet every other child by shaking hands and introducing themselves. With 15 children in the class, there would be 105 total handshakes as each child shakes hands with one less child until the last child who has already met everyone.
  • #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:
 
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  • #2
[tex]\sum_{i=1}^{15}i[/tex]
 
  • #3
No...Slightly wrong
 
  • #4
14....
 
  • #5
14......?
 
  • #6
It's not 120?
 
  • #7
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
no...sorry
 
  • #9
Lol I thought way too fast... 105!
 
  • #10
Ya..Now it's Correct...
 
  • #11
hmm, could someone explain this one to me?

Hey dontdistrbmycircles :)
 
  • #12
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
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.
 
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Likes gracy
  • #15
Damn it :grumpy:. Thanks!
 
  • #16
Oh...Am I correct?
 

What is the importance of the first day at school?

The first day at school is important because it sets the tone for the rest of the school year. It is the first impression for both students and teachers, and can impact the overall experience and success of the school year.

How can parents prepare their child for the first day at school?

Parents can prepare their child for the first day at school by talking to them about what to expect, practicing school routines such as waking up and getting ready on time, and visiting the school beforehand if possible. It is also important for parents to express excitement and positivity about their child's first day at school.

What should a student bring on their first day at school?

A student should bring any necessary school supplies, such as notebooks, pencils, and folders, as well as a backpack to carry them in. It is also important to bring a lunch or lunch money, and any required forms or paperwork that may be needed for the first day.

How can students make a good first impression on their first day at school?

Students can make a good first impression by being well-groomed, having a positive attitude, and being friendly and respectful to their teachers and classmates. It is also important to follow school rules and participate in class activities.

What can a student do if they feel nervous on their first day at school?

If a student feels nervous on their first day at school, they can try talking to a teacher or counselor about their feelings, taking deep breaths to calm themselves, or finding a familiar face in their class to sit with. It is also helpful to remember that it is normal to feel nervous and that things will get easier as the day goes on.

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