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CA Foundation · Quantitative Aptitude · Permutations and Combinations

How many 3-digit even numbers can be formed using the digits 1, 2, 3, 4, 5, 6 if repetition of digits is not allowed?

The answer is 60. Fill the restricted unit place first with one of 3 even digits, then the hundreds place with any of the 5 remaining digits, then the tens place with 4 remaining digits: 3 × 5 × 4 = 60.

  1. A60Correct
  2. B40
  3. C120
  4. D72

Explanation

The unit place must be even: 2, 4 or 6, giving 3 choices. The hundreds place then has 5 remaining digits and the tens place has 4. Total = 3 × 5 × 4 = 60. The value 120 counts all 3-digit numbers, ignoring the even condition.

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