To find a percentage divide the first number by the second.

=

=1.00
Now that you have your number, move the decimal point over 2 to the right and add your percentage sign.
100.00%
Your answer is 100%
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 answer should be -5 bc you substitute the 10 for x