A factory produces 3 bottles of sparkling water for every 7 bottles of plain water. If those are the only two products they produce, what percentage of their production is sparkling water? What percentage is plain?

70%

Step-by-step explanation:

So first we need to find the number of total bottles produced for every 7 bottles of plain water.

We can do this with:

3+7=10

So, for every 10 bottles produced, 7 bottles are plain water.

Now we can set up a fraction:

7/10

which is equivalent to 70 percent.