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6 People Shake Hands Once Each: How Many Handshakes in Total?
6 people meet and each shakes hands with every other person exactly once. How many handshakes took place in total?
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What is the answer to the 6 people handshake riddle?
The answer is 15. With 6 people, the number of unique handshakes is C(6,2) = 6×5÷2 = 15.
How do you calculate the number of handshakes?
Use the combination formula C(n,2) = n×(n-1)÷2. For 6 people that is 6×5÷2 = 15 handshakes.
Why isn't the answer 30?
Each handshake involves two people, so counting 6×5 = 30 double-counts every pair. Divide by 2 to get 15.