Okay for this question, you make a simple equation: (1/3)x=(1/4)y to represent the ratio between the milk and water. Then to find how many cups of water are needed for each cup of milk, you plug in 3 for x (because 1/3 times 3 equals one cup) and solve for your y value. Your final equation for solving should look like: (1/3)(3)=(1/4)y