SOLUTION: A serial number on a 5$ bill includes 3 letters followed 7 digits. Assuming the digits are randomly assigned, what is the probability that the serial number will contain at least f
Algebra.Com
Question 1153090: A serial number on a 5$ bill includes 3 letters followed 7 digits. Assuming the digits are randomly assigned, what is the probability that the serial number will contain at least five even digits? What is the average number of even digits that will appear in a serial number?
Answer by greenestamps(13200) (Show Source): You can put this solution on YOUR website!
The probability that any one digit is even is 1/2; the probability that it is odd is 1/2.
(1) P(5 of the 7 are even (and 2 are odd)) =
(2) P(6 of the 7 are even (and 1 is odd)) =
(3) P(7 of the 7 are even (and 0 are odd)) =
ANSWER: P(at least 5 are even) = 29/128
Without doing any fancy calculations, since the probabilities of each digit being even or odd are the same, on average half of the 7 digits will be even.
ANSWER: 3.5
RELATED QUESTIONS
The serial numbers on $5 bills include three letters followed by seven digits. Assuming... (answered by Boreal)
A manufacturer's automobile serial number consists of 2 letters of the alphabet, followed (answered by Fombitz)
A manufacturer's automobile serial number consists of two letters of the alphabet... (answered by edjones)
A manufactures automobile serial number consists of two letters of the alphabet followed... (answered by Fombitz)
A manufacturer’s serial numbers consist of 3 letters of the alphabet followed by 3... (answered by josmiceli)
A serial number must consist of four different digits, followed by two different letters. (answered by stanbon)
Some states have license plates formed by 3 letters followed by 3 digits. Both letters... (answered by stanbon)
A manufacturer’s serial numbers consist of 4 letters of the alphabet followed by 2... (answered by Hawksfan)
A manufacturer’s serial numbers consist of 2 letters of the alphabet followed by 2... (answered by Alan3354)