Multiple choice

How many 4 digit numbers can be formed out of the digits 0, 1, 2, 3 and 4 if no digit is repeated?

  1. 120

  2. 20

  3. 96

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For a 4-digit number from digits {0,1,2,3,4} with no repetition, the first digit cannot be 0 (otherwise it's a 3-digit number). So first digit has 4 choices (1,2,3,4). Second digit has 4 remaining choices (including 0), third has 3 choices, fourth has 2 choices. Total = 4 × 4 × 3 × 2 = 96.

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