what is the probability that the letters chosen are AA?
*Disclaimer, I don't know the whole problem so this may not be anywhere close to the right answer. If you edit it to include the whole problem, I'm sure I could be of more help*
I'm going to assume that you are choosing two letters of the alphabet at random. If this is true then, the first thing we need to find is the probability of choosing A, or 1/26. Since you are drawing twice, the full problem would be 1/26 x 1/26. This would be 1/676 chance or 0.15% (rounded to the nearest hundredth.)