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
Answer:

Step-by-step explanation:
We have the equation 
In order to solve for x, we need to get all of the x's to one side and everything else to the opposite side

First, we can add 1 to each side

Now, we can add x to each side

Next, we can divide each side by 2

And here is our answer.
The answer is D. My dad taught me an easy way to solve those kind of problems.You need to do (60×20)÷100. And since 60 and 20 both have a zero and 100 has 2 zeros, u can cross out all the zeros and just do 6×2 and divide that by 1 and so 20% of 60 is 12. Hope this helped :)