World problem

Question

Most nutritionists now agree that a healthy adult diet should include 25-35 g of fiber each day. A breakfast of 2 blueberry muffins, 1 orange, and a 1-cup serving of cereal contains 13 g of fiber; a breakfast of 1 blueberry muffin, 3 oranges, and a 1-cup serving of cereal contains 20.5 g of fiber; and a breakfast of 2 blueberry muffins and a 1-cup serving of cereal contains 8 g of fiber. How much fiber is in each of these foods?
A blueberry muffin contains
nothing g of fiber.

Answer 1

So the first hint is that the blueberry muffin has no fiber. That is a big help with the last sentence (the one with 2 blueberry muffins and a 1-cup serving of cereal. Now, take what you know about the cereal and apply that knowledge to the other two meals.