Question

What are the total amount of choices possible if an individual is to create a 4 digit password using the digits 0 through 9 inclusive, but not using the digit 0 as the first character of the password?
a.
39
b.
900
c.
399
d.
9000

Answer 1

Answer: d. 9000.

Reason: The first digit can be 1–9 (9 choices). Each of the remaining three digits can be 0–9 (10 choices each). Total = 9 × 10 × 10 × 10 = 9,000.