D is the answer.
If f(x) or y = 2x, the inverse is x = 2y or y=x/2 which is not f(x).
I believe the answer is 9, because 1/3 is .33 so 33%. so 33% is equal to 3 buttons and add another 66% which would be another 6 buttons would add up to 99% in all. after that I don't think they would add a quarter of a button.
The value of X is 5 and QR is 34
Answer:

Step-by-step explanation:
