A password for a computer uses four digits from 0 to 9, inclusive. What is the probability that the digits of the password solely consist of prime numbers or zero?
Answers
A) 1/32  B) 1/16  C) 1/8  D) 2/5  E) 1/2
To calculate all the possibilities, there are 10 choices for each digit. The number of possibilities for five digits is 10 × 10 × 10 × 10 = 10,000 possible combinations.   Prime numbers constitute 2, 3,and 5 . In addition to zero, this is 4 total possibility for each digit. So the number of satisfactory variants is 4 × 4 ×4 × 4 So the probability is 1/2 × 1/2 × 1/2 × 1/2 = 1/16.   The right answer is choice (1/16).
<result>B</result>
A password for a computer uses four digits from 0 to 9, inclusive. What is the probability that the digits of the password solely consist of prime numbers or zero?