Using only the digits 1 through 6, how many five-digit numbers can be formed in which at least one digit is re

Question

*repeated

Answer 1

Was the question going to be "how many five-digit numbers can be formed in which at least one digit is repeated?" There are 6*6*6*6*6 different five-digit numbers that you can form.

Of these, 6*5*4*3*2 have no repeated digit.

The answer to your question is therefore 6*6*6*6*6 minus 6*5*4*3*2, which is 8376 - 720, which is 7656.

Answer 2

The easiest way to solve this without going bonkers is to look at this as
Answer = all possible ways of forming 5-digit numbers - ways of forming non-repeating numbers.

The all possible ways is simply 6^5 power (about 7800).
The non-repeating ways is 6 x 5 x 4 x 3 x 2 = 720
Do the indicate subtraction.

Answer 3

At least one digit is re-what? Repeated?