During the African-US summit last year, 10 presidents left the conference room and greeted one another. Assuming no 2 presidents repeatedly greeted themselves, how many total handshakes were effected?
Check your answer:-
Click here to See Answer
Answer is 45 handshakes. The first president greeted 9 presidents, the second 8 and so on, so 9+8+7+6+5+4+3+2+1. This gives 45 handshakes.
in permutations and combinations way
A handshake is possible with two people, so it is similar to How many ways you can select two people out of 10.
i.e. 10C2 = 10!/(8!*2!) = 9*10/2 = 45
Facebook Comments
45 handshakes. Becoz if everyone would handshake each other then if 10 persons are then 9 +8+7+6+5+4+3+2+1=45. n thats d answer!