2022 AMC 10B Problem 3
Problem 3 of 25EasierNumber TheoryCounting & Probability
How many three-digit positive integers have an odd number of even digits?
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Solution
There are choices for the hundreds and tens digits. Once those two digits are fixed, the units digit must have whichever parity makes the total number of even digits odd. There are always digits of the required parity (including among the even digits).
Therefore, the number of integers is
Thus, the answer is D .