At a certain company, passcodes numbers must be composed from the ten digits 0-9 and be from 3-5 digits long. Use the methods illustrated in the text book to answer the following questions. (a) If repetition is allowed, since there are 10 choices for each digit, the number of passcodes of length n is O 10n O n^10 O n+10 O 10^n (b) The total number of passcodes consisting of 3, 4, or 5 symbols is O 1000 O 111000 O 36000 O 75000 (c) How many passcodes contain no repeated symbols? (Hint: In this case, if digits are entered into a passcode one by one, the number of choices for each entry decreases by 1 as each additional digit is entered.) The total number of passcodes consisting of 3, 4, or 5 digits, each of which has no repeated digit, is O 1000 O 75000 O 111000 O 36000 (d) How many passcodes have at least one repeated digit? The number of passcodes with at least one repeated digit is O 75000 O 1000 O 111000 O 36000 (e) What is the probability that a passcode chosen at random has at least one repeated symbol? (Round your answer to the nearest percent.) O 70% O 34% O 68% O 66%