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Hawkes Learning e Chegg Study | Guided S C Secure | https://learn.hawkeslearning.com/Portal/Lesson/lesson-certify Save & End Certify Lesson: 7.3 Using Counting Methods to Fin. MANUEL IBARRA Question 2 of 14, Step 1 of 1 Correct Kiara sets up a passcode on her tablet, which allows only eight-digit codes. She has heard that it's more secure if a digit is repeated in the passcode. A spy sneaks a look at Kiara's tablet and sees her fingerprints on the screen over seven numbers. What is the probability the spy is able to unlock the tablet on his first try? Express your answer as a fraction in lowest terms or a decimal rounded to the nearest millionth. Answer Keypad How to enter your answer Submit Answer 8 2017 Haikes Learning 1:01 PM 10/8/2017 Search the web and Windows

Explanation / Answer

Please read the answer carefully.

There are 8 digits in this codes and the spy knows 7 were used to fill, so one number was a repeat.

7! is the no of ways of arragining 7 numbers. In the 8th place, any of the 7 would have been used. So, 7!*7 total ways in which combo was put.

Out the of 7!*7 combo, 1 is going to be right.

So, P(right in first attempt) =gets right in first try/ total combos = 1/7!*7 = .001389

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