question!!

[stones2409]

It was the 1st 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 9 children in the class, how many total handshakes were there?

Thank You

[burnhal]

8+7+6+5+4+3+2+1

36

[emeritus]

Taken from another site

The class has 9 children. The first child shakes hands with the other 8 children. The second child has already shaken hands with the first child, and so has to shake hands with only the other 7 children and so on. The second-last child has to shake hands with only one child, and the last child has already met all the children. so the number of handshakes is

8+7+6+5+4+3+2+1 = 36

[stones2409]

Thank You burnhal & emeritus