Question 1091994: Hi very helpful tutors, I have one more multiple type word problem on which the second part has got me completely stumped!
Members of a video club choose a PIN consisting of two letters and two digits. How many PINs are possible if letters and digits may be repeated? (I now understand how to get the answer to this.) But then it asks: How many are possible if neither letters nor digits may be repeated?
I don't understand what they mean by "repeated", and therefore I have no idea how to get the answer. Please explain! Thank you for your help!
Answer by math_helper(2461)   (Show Source):
You can put this solution on YOUR website!
By repeated they mean if you choose, say, the letter A then you can still choose a letter A for the 2nd letter.
(And of course, the same logic applies to the digits, if a number is chosen and can be repeated, then you can choose that same number again). Note that some problems will use the term "with replacement" to indicated "repeats allowed."
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So for the no repeats allowed case: you have 26 choices of letters for the first one, then 25 choices for the 2nd.
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You probably have enough info now to solve it. Send a message if you want me to check your answer.
Hope this has helped you!
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