# A.2.4.3 Calories from Protein and Fat

One gram of protein contains 4 calories. One gram of fat contains 9 calories. A snack has 60 calories from *p* grams of protein and *f* grams of fat.
The equation 4p + 9f = 60 represents the relationship between these quantities.
Determine if each pair of values could be the number of grams of protein and fat in the snack. Explain your reasoning.
a. 5 grams of protein and 2 grams of fat
b. 10.5 grams of protein and 2 grams of fat
c. 8 grams of protein and 4 grams of fat

If there are 6 grams of fat in the snack, how many grams of protein are there? Show your reasoning.

In this situation, what does a solution to the equation 4*p* + 9*f* = 60 tell us? Give an example of a solution.

Here is another equation about a different snack 4x + 9y = 110. Remember a gram of protein has 4 calories and a gram of fat has 9 calories. What does the equation tell us about the calories in this new snack?

In this situation, what does it mean to solve the equation?

Is the combination of 11 grams of protein and 5 grams of fat a solution to the equation? Why or why not?

Consider the equation 4(5) + 9*y* = 110. What does it tell us about the snack?

What does it mean to solve this equation?