Question

Let A be the set of all strings of decimal digits of length 5. For example 00312 and 19483 are two strings in A. You pick a string from A at random. What is the probability that the string has no 4 in it

Answer 1

0.59049

Explanation:

Set of all digit strings of length 5

Digit range = (0 - 9) = 10

Length of digit = 5

Total possible outcomes = 10^5 = 100000

String without a 4 ;

Digit range = (0,1,2,3,5,6,7,8,9) = 9

Length of digit = 5

Required outcome = 9^5 = 59049

Required outcome / Total possible outcomes

59049 / 100000

= 0.59049