You are given the amount of water a Clydesdale drinks in 4 days, but because you want 28 days, you need to multiply that value by something. You find what you need to multiply it by, by dividing 28 by 4, which gives you 7. Now, you can do 120 × 7 = (100 × 7) + (20 × 7) = 840 gallons of water. I hope this helps!
