A four-digit code can consist of the digits 0 ~ 9 except that it does not contain the digits 1, 3, and 4 at all. If repeated digits are allowed, what is the probability that it has at least one even digit?
Select the correct option
A) 130/201
B) 320/401
C) 820/901
D) 1320/1401
E) 2320/2401
P(no even digits) = 3/7*3/7*3/7*3/7 = 81/2401   P(at least one even digit) = 1 - 81/2401 = 2320/2401   The answer is 2320/2401.
<result>E</result>
A four-digit code can consist of the digits 0 ~ 9 except that it does not contain the digits 1, 3, and 4 at all. If repeated digits are allowed, what is the probability that it has at least one even digit?