In all you have 54 buttons because if you add 10 plus 10 that equals 20 plus 34 and that gets 54 buttons in all
Probability=number of specific outcomes / total number of possible outcomes...
Since they want to know the probability of getting all of the colors the probability is just one.
The sum of all probabilities is always equal to one. In this case:
1/4+1/4+1/4+1/4=1