A four-digit code can consist of the digits 0 ~ 9 except that it does not contain the digits 1, 2, 3, 5, and 6 at all. If repeated digits are allowed, what is the probability that it has at least one even digit?  Answers:
A) 97/100
B) 121/125
C) 343/400
D) 609/625
E) 729/1000
P(no even digits) = 2/5*2/5*2/5*2/5 = 16/625   P(at least one even digit) = 1 - 16/625 = 609/625   The answer is 609/625.
<result>D</result>
A four-digit code can consist of the digits 0 ~ 9 except that it does not contain the digits 1, 2, 3, 5, and 6 at all. If repeated digits are allowed, what is the probability that it has at least one even digit?