John can complete a paper route in 20 minutes. Steve can complete the same route in 30 minutes. How long will it take them to co
2 answers:
You might be interested in
Answer:
The probability is
Step-by-step explanation:
If she has n distinct password candidates and only one of which will successfully log her into a secure system, the probability that her first first successful login will be on her k-th try is:
If k=1
Because, in her first try she has n possibles options and just one give her a successful login.
If k=2
Because, in her first try she has n possibles options and n-1 that are not correct, then, she has n-1 possibles options and 1 of that give her a successful login.
If k=3
Because, in her first try she has n possibles options and n-1 that are not correct, then, she has n-1 possibles options and n-2 that are not correct and after that, she has n-2 possibles options and 1 give her a successful login.
Finally, no matter what is the value of k, the probability that her first successful login will be (exactly) on her k-th try is 1/n