It states that Bob needs 2 cups of the concentrate to make the juice. Bob has 6 cups of the concentrate all-together. It also says that you have to mix the concentrate with 3.5 cups of water. So, if he has 6 cups, he need to multiply the 6 cups of concentrate by the 3.5 cups of water to figure out how many cups he can make. On the calculator it would look like 6•3.5