+758 If seven people meet each other and each shakes hands only once with each of the others, how many handshakes will there have been?
+37146 Seven people must shake hands with six other people.... you might think that is 42 handshakes ....BUT...each handshake involves TWO people so the total number of handshakes is 1/2 of 42 = 21 handshakes.
+42 To find the number of handshakes, we can use the formula for the sum of the first n-1 positive integers, which is given by (n-1)n/2.
In this problem, n is equal to seven since there are seven people.
Using the formula, the number of handshakes will be (7-1) * 7/2 = 6 * 7/2 = 42/2 = 21.
Therefore, there will be 21 handshakes in total.
