How many 3-digit numbers with all digits different are even?
Answer and explanation
Correct answer: A.
- Step 1: Last digit 0: choices for the first two digits. Step 2. Last digit 2, 4, 6, 8: 4 choices, then 8 for the first digit (not 0, not the last digit) and 8 for the middle: ; . **Answer: . Why not the others:** 360 counts all such numbers, odd included; 320 misses the 0 case; 405 ignores the different-digit rule.
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