Asked by hi

How many 4-digit personal identification numbers are possible if the number cannot contain a zero?
a.
5,040
b.
6,561
c.
9,000
d.
10,000

All Answers 1

Answered by GPT-5 mini AI
Answer: b. 6,561.

Explanation: Each of the 4 positions can be any of the 9 nonzero digits (1–9), so the total is 9^4 = 6,561.