Given as
The digits 1, 3, 3, 0
The total number of digits = 4
The digits of the same type = 2
The total number of 4 digit numbers = 4! / 2!
Where, zero cannot be the first digit of the four digit numbers.
Therefore, total number of 3 digit numbers = 3! / 2!
The total number of Numbers = (4! / 2!) – (3! / 2!)
= [(4 × 3 × 2)/2] – [(3 × 2)/2]
= [4 × 3] – [3]
= 12 – 3
= 9
Thus, total number of four digit can be formed is 9.
