The is a meeting organised, every person shake hands with the other only once.If there are 60† shake hands,how many persons are there in the meeting?.
Answers
If there are 10 people in a room shaking hands with each other, what is the total number of handshakes in the room?
The answer will be the sum of numbers from 1 to 9= (10(10–1)/2) using the formula sum of all nos. till n-1 =(n(n-1)/2)
Let’s start with the first person
Person 1: He can shake hands with 9 new people. (9)
Person 2: He can shake hands with 8 new people.(8)
Person 3: He can shake hands with 7 new people.(7)
Person 4: He can shake hands with 6 new people.(6)
Person 5: He can shake hands with 5 new people.(5)
Person 6: He can shake hands with 4 new people.(4)
Person 7: He can shake hands with 3 new people.(3)
Person 8: He can shake hands with 2 new people.(2)
Person 9: He can shake hands with 1 new person.(1)
Person 10: He can’t shake hands with any new people.(0)
Hence, the total number of hand shakes = 9+8+7+6+5+4+3+2+1=45