We know that 8/75 patients prefer bubblegum toothpaste. We want to make the ratio, “_:1500”. To do this, we divide 1500 by 75 to get 20. The ratio is now p : 1500. Now, we must do the same thing on both ends: since 75 times 20 got us 1500, 8 times 20 gets us 160. So, 160 out of the dentist’s 1,500 patients prefer bubblegum toothpaste.