### Brain Teasers

# The Handshakes.

Four people shake hands with each other only once. How many handshakes occurred?

### Answer

Six.If each person is named A, B, C, and D, then the six handshakes are AB, AC, AD, BC, BD, and CD

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## Comments

Classic math teaser, and I liked it. If your still on the site, keep them comin.

ugh. That problem is in my math book!!!!!

this one was way easier than the one where 99 people tip their hat to each other once.

WAY TOO EASY.

lol i had one just like this except it was 28 handshakes how many people were there i liked it except its a little too much like my math right now. ugh

i thought it was 2

cuz A&B shake hands while C&D shake hands

whoops!

cuz A&B shake hands while C&D shake hands

whoops!

Simple binomial to determine the number of ways to choose two elements from a set of four.

4! / ((4-2)! x 2!) = 24 / 4 = 6

4! / ((4-2)! x 2!) = 24 / 4 = 6

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