A briefcase has a three-digit lock code that does not include zero as a digit. What is the probability that the lock code consists of all even digits if the same digit is not used more than once in the lock code?
+36916 total codes possible with no zero 9 x 8 x 7 = 504
4 out of 9 numbers are even 4 x 3 x 2 = 24 all even
24/504 or 1/21
