How many 12-digit decimal sequences are there that

[Guest]

Here's the problem:

How many 12-digit decimal sequences are there that start and end with a sequence of at least two 3s? We think it's just 12 choose 8, is that all that's needed?

 

[arthur ohlsten]

here is the 12 digit sequence
3 3 x x x x x x x x 3 3
each x can be any of 10 digits [ 0 to 9]
or we have 10^8
10^8 ,12 digit sequences can be generated where the first and last 2 are threes
Arthur

 

[Guest]

Thank you.