Caleb needs to create an 8-digit password using only numbers. How many different passwords are there if he wants to use 00 exactly once?

Answer 1

Caleb uses 00 exactly once, leaving 6 digits from 1 to 9, or 10^6, or 1 million other combinations of digits to choose from. Since the 00 can be the first two digits, the second two, etc., up to 7 different spots in the number, meaning 7 million different passwords to choose from. ☺☺☺☺

Answer 2

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