Discrete mathematics

[smarika]

How many strings of 5 uppercase English letters are there where the first and third letters are the samw and the sttings is not a palindrome? ( there are 26 uppercase letters and not allowed ro use factorials) what are the steps and how to solve this problem?

 

[Deleted member 4993]

How many strings of 5 uppercase English letters are there where the first and third letters are the samw and the sttings is not a palindrome? ( there are 26 uppercase letters and not allowed ro use factorials) what are the steps and how to solve this problem?

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.