Question
How many 3-digit numbers can be formed from the digits 1, 2, 3, 4 and 5 assuming that repetition of the digits is not allowed.
Solution
Number of ways in which place (x) can be filled = 5
m = 5
Number of ways in which place (y) can be filled = 4 (∵ Repetition is not allowed)
n = 4
Number of ways in which place (z) can be filled = 3 (∵ Repetition is not allowed)
p = 3
∴ By fundamental principle of counting, the total number of 3 digit numbers formed
= m x n x p = 5 x 4 x 3 = 60.
