Word problem

Question

Most nutritionists now agree that a healthy adult diet should include 25 minus 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

2 x + y + z = 13

x + 3y + z = 20.5

2x + + z = 8

subtracting EQ 1 MINUS Eq3, y = 5

Substituting y=5 , simplifying and solving,

the system becomes:

2x + z = 8

x + z = 5.5

subtracting these equations:

x = 2.5

which forces z = 3

2(2.5) + 5 + 3 = 5+5+3 = 13 <--- yes it checks

2.5 + 3(5) + 3 = 2.5 + 15 + 3 = 20.5 <--- yes it checks

2(2.5) + 3 = 5+3 = 8 <-- yes it checks

the blueberry muffin has 2.5 grams of fiber.

the orange has 5 grams of fiber

the cereal has 3 grams of fiber.

that seems strange to me that the orange has more fiber than the muffin and the cereal