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James has a 5 digit passcode on his computer. The first three digits are numbers from 0 to 9 and the last two digits are letters from the alphabet. If the numbers and letters can repeat, what is the probability that the passcode is 417GR?

1338000

5676000

316900

1676000

User Omar Jayed
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2 Answers

6 votes

ay 30 porciento de probabilidad de que sea ese

para mi es 029ABI

User Raygreentea
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5 votes

Answer:

Explanation:

This is a simple permutations problem! Let's understand, analyze and solve !

First, we understand that there are five spaces that need to be filled: _ _ _ _ _

Second, we should know HOW MANY can go in those spaces: as the problem says, ANY number 0-9,or capital letters,or lower case letters. Numbers 0-9 give us 10 options, all lowercase letters give 26 options, and capital letters give us 26 options. Adding these together, that is 62 options.

Third, we see that since each space can give 62 options (as numbers and letters can be repeated), you multiply 62 by itself five times: 62 * 62 *62 *62 *62. This gives us 916132832 permutations for a password!

**For future reference, it is good to note that if the problem said "each letter, lowercase letter, or capital letter can only be used once". then the answer would be 62 * 61 * 60 * 59 * 58. The reason for this is that once a letter or number is used, it must be removed from the "options" total that we figured out in the 2nd paragraph above. So at first you have all 62 options, but once one is picked it cant be used in the second slot, so now there are only 61 options, so on and so forth.

User Pamcevoy
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