It says
the probability of Hulk getting angry is 1/8.
Here , the trick of the question is that answer is already given in the question.
Now for any day the probability of Hulk getting angry will remain the same . i.e. 1/8.
So ,
Probability of Hulk getting angry tomorrow will remain the same.
Hence we get
Probability of Hulk getting angry tomorrow = 1/8