Question

18. At a certain company, passwords must be from 3-5 characters long and composed of the 26 letters of the alphabet, the ten digits 0-9, and the 14 symbols !,@,#,$,%,^,&,*,().-+,{, and ). (As a note, the password does not REQUIRE at least one character of each type. In other words, it is fine if your password doesn't have any digits or is only special symbols.) a. How many passwords are possible if repetition of characters is allowed? [4 points] b. What is the probability that a password using three characters chosen has at least one repeated character? [4 points]

Answer 1

Answer:- Summarized the letters, alphabets and symbols provided in the problem, @ Possible passwords using (3,4,5 length) 26 different letters, ten digits and 14 symbols; - total symbols = 26+14 +10 = 50: combinations - 3 (letter length) +4 +5 15094 + (50)3 t (50)5 - 125000 + 6250000 + 312500000 318,875,000 Ans. -

6 In (50) In 3 symbol password, total combinations Symbols having one repitition 3 X 50 X 50 So, probability 50 x 56x3 50x50x50 3 50 Au *
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