Question

Four glasses of milk and 3 snack bars have a total of 82 carbohydrates (carbs), and 2 glasses of milk and 4 snack bars have a total of 76 carbs. Determine how

many carbs are in one glass of milk and in one snack bar.

Answer 1

• milk: 10 carbs
• snack bar: 14 carbs

Explanation:

Let m and s represent the carbs in the milk and snack bar, respectively. The given relations are ...

4m +3s = 82

2m +4s = 76

Subtracting the first equation from twice the second gives ...

2(2m +4s) -(4m +3s) = 2(76) -(82)

5s = 70 . . . . . . . simplify

s = 14 . . . . . . . divide by 5

We substitute this into the second equation to find m.

2m +4(14) = 76

m +28 = 38 . . . . divide by 2

m = 10 . . . . . . subtract 28

There are 10 carbs in a glass of milk; 14 carbs in a snack bar.