There are 100 zombies in the warehouse some have turned into zombies and some are still alive if the ratio zombies to total people is 1:5 how many zombies are on the warehouse

Tomas used 3 1/3 cups of flour and now has 1 2/3cups left. which equation can he use to find f, the number of cups of flour he had to begin with? f+3 1/3=1 2/3 f-3 1/3=1 2/3 3 1/3f=1 2/3 f/3 1/3=1 2/3