KCET2018MathematicsPermutation and Combination
Everybody in a room shakes hands with everybody else. The total number of handshakes is 45. The totalnumber of persons in the room is
Options
- A( 09 )
- B( 10 )
- C( 05 )
- D( 15 )
Correct answer
B. ( 10 )
Step-by-step solution
Total number of handshakes are ( 45 . ) So, total number of persons are [ array l n 2 =45 n(n-1) 2 =45 n(n-1)=90 10 9 n(n-1)=10(10-1) n=10 array ]