Question

There are 100 persons in a room. Find the total no of handshakes

Answer 1

let's take the first person,he can shake 99 people

the second one shakes 98 (as he has shook already with the first one)

the third, 97 and so on...

so to sum up the total number of shakes = 99+98+97+96+....+1=(1+99)*99* 1/2=4950 shakes

Answer 2

Answer:

16 people

Step-by-step explanation:

If there are n people, there will be n(n - 1)/2 handshakes

Find n, given that there are 120 handshakes

n(n - 1)/2 = 120

n(n - 1) = 240

n² - n - 240 = 0

(n - 16) (n + 15)  = 0

n = 16 or n = - 15 (rejected, since number of people cannot be negative)

Answer: There are 16 people at the affair