Questions
Every body in a room shakes hands with everybody else. The total number of hand shakes is 66. The total number of persons in the room is
detailed solution
Correct option is B
Let total number of persons be n.Since, total number of hand shakes = 66 ∴ nC2 =66⇒n(n−1)2=66⇒ n2−n−132 =0⇒ (n−12)(n+11) =0⇒ n =12 [∵n cannot be negative ]Similar Questions
is equal to
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