Question

In the Suniti Building in Mumbai there are 12 floors plus
the ground floor.9 people get into the lift of the building
on the ground floor.The lift does not stop on the first floor.
If 2,3 and 4 people alight from the lift on its upward
journey,then in how many ways can they do so?(Assume
they alight on different floors)

Answer 1

they go 2,3,4,5,6,7,8,9,10
1+1+1+1+1+1+1+1+1=9