Question 155471: Do exponential functions only model phenomena that grow, or can they also model phenomena that decay? Explain what is different in the form of the function in each case.
I would appreciate a detailed answer.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A password consists of 11 characters. A user must select a password consisting of AT LEAST 2 lower case letters, 2 upper case letters, 2 digits AND 2 special characters. How many passwords exist?
#lower case letters = 26
#upper case letters = 26
#digits = 10
#special characters = 32
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Comment: I'm assuming repetition is not allowed.
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Pick 2 lower case: 26C2 leaving 24
Pick 2 upper case: 26C2 leaving 24
Pick 2 digits: 10C2 leaving 8
Pick 2 special characters: 32C2 leaving 30
Pick 3 of anything without repeating previous selections 86C3
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Multiply all those picks, then multiply by 11! to get all the arrangements.
I get 9.410585 x 10^16
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Cheers,
Stan H.
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