## How many different passwords are possible if no character digit or letter may be repeated?

If no characters can be repeated, then there are 36 choices for the first, 35 for the second, 34 for the third, 33 for the fourth, 32 for the fifth, and 31 for the sixth. The total number of passwords would be 36 × 35 × 34 × 33 × 32 × 31 or 1,402,410,240. or 308,915,776 possible passwords.

## How many such 3-letter passwords are possible?

So, there are total 26*25*24 possible values of (xyz).

## How many different 4 letter passwords can be made if repeats are allowed?

The password chosen must have 4 letters total. If each letter has to be distinct, meaning that the letters all have to be different, then there are 7*6*5*4 = 840 ways. If the letters are allowed to be repeated then there are 7*7*7*7 = 7^4 = 2,401 ways.

## How many variations of 1234 are there?

There are 10,000 possible combinations that the digits 0-9 can be arranged into to form a four-digit code.

## How many 5 digit PIN numbers can be made if repetition is allowed?

How many number of 5 digits can be formed? Repetition of digits is allowed. ∴ Each place out of unit, 10th, 100th and 1000th can be filled in 5 ways. Total numbers =4×5×5×5×5=2500.

## What is the probability of guessing my 4 digit PIN number in 5 attempts?

Research suggests thieves can guess one in five PINs by trying just three combinations. How easy would it be for a thief to guess your four-digit PIN? If he were forced to guess randomly, his odds of getting the correct number would be one in 10,000—or, if he has three tries, one in 3,333.

## How many five digit numbers can be formed from the digits 0 1 2 3 and 4 if repetitions are not allowed?

6*6*5*4*3 = 2160 is the total no. of digit that can be formed from 0,1,2,3,4,5,6 with no repetition.

## How many two digit even numbers are possible?

The total number of possible 2-digit even numbers is 9*5 = 45, if repetition is allowed.

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