For this question, we can make the number equal to n. Since two less than it is equal to ten, we know that we are dealing with subtraction. In addition, we know that doing something to n makes it equal to 10. And that something is subtracting two from it. that means that the equation that represents this scenario is n - 2 = 10.
66.5 divided by 3.5 is 19.
There are 60 minutes in one hour.
Divide 60 minutes by 10 minutes.
You get 6. That means you would need 6 recycled bottles to power a washing machine for one hour (that will be awesome if that were the case).
Have an awesome day! :)