A number is called flippy if its digits alternate between two distinct digits
A number is called flippy if its digits alternate between two distinct digits. For example, 2020 and 37373 are flippy, but 3883 and 123123 are not. How many five-digit flippy numbers are divisible by 15?
(A) 3 (B) 4 (C) 5 (D) 6 (E) 8
answer: B
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