Question

One gram of protein contains 4 calories. One gram of fat contains 9 calories. A snack has 80 calories from x grams of protein and y grams of fat. 80= 4x + 9y

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

Answer 1

6,5g of protein

Explanation:

80=4x + 9y

y=6 ( "6 grams of fat")

so: 80=4x+9.6

80-54= 4x

26/4=x

x(protein)= 6,5

Answer 2

6.5 grams

Explanation:

To find the value of x that corresponds to the given value of y, put that y-value into the equation and solve for x.

80 = 4x +9·6

26 = 4x

26/4 = x = 6.5

There are 6.5 grams of protein in the snack.