Multiple choice

Using digits 1, 4, 5, 8 and 9, how many 5-digit even numbers can be formed such that all the digits are distinct?

  1. 24

  2. 48

  3. 72

  4. 96

  5. 120
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

To be even, the last digit must be 4 or 8. If the last digit is 4, there are 4 choices for the first, 3 for the second, 2 for the third, and 1 for the fourth (4 * 3 * 2 * 1 = 24). If the last digit is 8, there are also 24 ways. Total = 24 + 24 = 48.

AI explanation

For a number to be even, its last digit must be even, leaving only the digit 8 for the units place. The remaining four positions can be filled by the remaining four digits in 4P4 ways. Calculating this gives 4P4 = 24. Therefore, 24 such numbers can be formed.

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