Question

A safe has a 4-digit lock code that does not include zero as a digit and no digit is repeated. What is the probability of a lock without all even digits?

There
to get a lock code with all even digits.

There are 3,024 different 4-digit lock codes.

There are
to get a lock code without all even digits.

The probability of a 4-digit lock code without all even digits is
.

Answer 1

There are 24 ways to get a lock code with all even digits.

There are 3,000 ways to get a lock code without all even digits.

The probability of a 4-digit lock code without all even digits is 3000/3024 = 125/126 (≈ 0.99206).