Walter is mixing cement for his new patio. He knows he needs to use water-to-cement ratio of 20 to 30. What percent of his total mixture is water?

Question

I know the answer just don’t know how to explain

Answer 1

If he uses 20 parts of water and 30 parts of cement, he has a total of 50 parts.  Of that 50 parts, only 20 parts is water. Since % means what fraction of the whole expressed in hundredths, simply divide and multiply by 100. Thus,

20/50 (x100%) = 40%.