Python Program for Permutations In Which N People Can Occupy R Seats In A Classroom

Which n people can occupy r seats in a classroom in Python

Here, we will discuss program for Permutations In Which N People Can Occupy R Seats in python .In this python program, we will be defining the number of ways in which N number of students can occupy R number of seats. Take an example Ten friends enter the classroom late and all the seats are occupied by toppers of the college and now only Six seats are available so in how many ways are those Ten friends will occupy Six seats although 4 students have to leave the classroom. We will use math library for factorial function in building of this program.

Problem Statement :

In a classroom some of the seats are already occupied by students and only a few seats are available in the classroom. The available seats are assumed as r and n number of students are looking for the seat. We need to find in how many different permutations n number of students can sit on r number of chairs.


  • Input number of students in n
  • Input number of seats in r
  • Use permutation formula { factorial(n) / factorial(n-r) }
  • Print Output
Permutation in which n people can occupy in python

Python code

# Permutations in which n people can occupy r seats

# function for factorial
def factorial(num):
    fact = 1
    for i in range(num, 1, -1):
        fact *= i
    return fact

# main program
# user input
n = int(input("Enter number of people: "))
r = int(input("Enter number of seats: "))

# finding all possible arrangements of n people on r seats
# by using formula of permutation
p = factorial(n) // factorial(n - r)

# printing output
print("Total possible arrangements:", p)


Enter number of people: 10
Enter number of seats: 6
Total possible arrangements: 151200

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6 comments on “Python Program for Permutations In Which N People Can Occupy R Seats In A Classroom”

  • Nikita

    n = int(input(“Enter the number of students: “))
    r = int(input(“Enter the number of seats: “))
    a = n – r

    def calc_fact(number):
    fact = 1
    while number > 0:
    fact = fact * number
    number -= 1
    return fact

    t_o_w = int(calc_fact(n) / calc_fact(a))
    print(“Total number of ways are: “, t_o_w)

  • Sonal

    num=int(input(“Enter the number of students “))
    r=int(input(“Enter the number of seats “))
    for i in range(1,num+1):
    for j in range(1,(num-r)+1):
    print(“{} people can occupy {} seats in {} ways”.format(num,r,w))

  • rajat

    Just 4 LINES.
    import math
    n = int(input(“Enter the number of Students:”))
    m = int(input(“Enter the number of Seats:”))
    print(math.perm(n, m))

  • premkumar

    Python program to calculate number of ways in which N people can occupy R seats
    import math