The conversation between human and AI assistant.
How many 3 digit even numbers can be formed from 1, 2, 4, and 5 with no repetition?
I see. Is there any other way to approach this problem?
One way is to use permutation. We have 4 choices for the first digit, 3 choices for the second (since one digit has already been used), and 2 choices for the third. Then we have to divide by 2 to account for the fact that the last digit can only be 2 or 4. So the answer is (4 x 3 x 2)/2 = 12.