Question

the total number of 5 digit numbers that can be composed of distinct digits form 0 to 9 is

Answer 1

NDA exam question
for solution refer attachment
answer is option 3

Answer 2

Total number of possible digit = 10

(They are  0, 1, 2, 3, 4, 5, 6, 7, 8 and 9)

Number of choices for the 1st digit = 9

(excluding the digit 0, since a number cannot start with zero)

Number of choices for the 2nd digit = 9

(any digit except the one that is already used as the 1st digit)

Number of choices for the 3rd digit = 8

(any digit except the ones that are already used as the 1st and 2nd digit)

Number of choices for the 4th digit = 7

(any digit except the ones that are already used as the 1st, 2nd and 3rd digit)

Number of choices for the 5th digit = 6

(any digit except the ones that are already used as the 1st, 2nd, 3rd and 4th digit)

Total possible combinations = 9 x 9 x 8 x 7 x 6 = 27216

Answer: (c) : 27216