SOLUTION: how many 4-digit pins are possible if the first digit may not be a zero, and one of the digits may be repeated?

SOLUTION: how many 4-digit pins are possible if the first digit may not be a zero, and one of the digits may be repeated?

Algebra.Com

Question 412530: how many 4-digit pins are possible if the first digit may not be a zero, and one of the digits may be repeated?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
9*10*10*10 if you mean any digit can be repeated.
If one of them, and not the others, can be repeated, you'll have to clarify that.
= 9000 PINs

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