In How many ways can 4 people be seated in a row containing 5 seats?
To find :number of ways in which 4 people can be seated in a row containing 5 seats.
The possible number of ways in which 4 people be seated in a row containing 5 seats =7P4 (There are 5 places to be filled with 4 persons where arrangement doesn’t matter.)
7P4
…(nPr
)
=7 × 6 × 5 × 4
=840
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