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1. In how many ways can seven friends be seated in a row having 35 seats, such that no two friends occupy adjacent seats?
They create 29 slots - one on the left of each seat and one on the right of the last one.
We can place the 7 friends in any of these 29 slots i.e. 29P7 ways.
Solution:
First let us consider the 28 unoccupied seats.They create 29 slots - one on the left of each seat and one on the right of the last one.
We can place the 7 friends in any of these 29 slots i.e. 29P7 ways.