In how many ways can 7 people line up at a ticket window of a cinema hall?

To find: number of arrangements of 7 people in a queue.


Here there are 7 spaces to be occupied by 7 people.


Therefore 7 people can occupy first place.


Similarly, 6 people can occupy second place and so on.


Lastly, there will be a single person to occupy the 7 positions.


Formula:


Number of permutations of n distinct objects among r different places, where repetition is not allowed, is


P(n,r) = n!/(n-r)!


Therefore, permutation of 7 different objects in 7 places is


P(7,7) =


= = = 5040.


Therefore, the number of possible ways is 5040


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