Hannah is making banana bread. She needs to use 3 cups of flour for every cup of banana mush. It takes 4 bananas to make one cup of mush. If Hannah uses 20 bananas, how many cups of flour should she use?
First find the number of cups of banana mush Hannah gets: 20 bananas / 4 bananas/cup = <<20/4=5>>5 cups
Then multiply the number of cups of mush by the ratio of flour to mush to find the number of cups of flour: 5 cups mush * 3 cups flour/1 cup mush = <<5*3=15>>15 cups flour
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