Question

4 glasses of milk and 2 snack bars have a total of 86 carbohydrates​ (carbs), and

2 glasses of milk and 3 snack bars have a total of 69 carbs. Determine how many carbs are in one glass of milk and in one snack bar.

Answer 1

There are 15 carbs in one glass of milk and 13 carbs in one snack bar.

Explanation:

Let m be the number of carbohydrates in one glass of milk and

Let s be the number of carbohydrates in one snack bar

Then according to given information

The system of equations will be:

`4m+2s = 86\\2m+3s = 69`

Multiplying equation 2 by 2 and subtracting from equation 1

`2(2m+3s) = 69*2\\4m+6s = 138`

Subtracting from equation 1

`4m+2s-(4m+6s) = 86-138\\4m+2s-4m-6s = -52\\-4s = -52\\(-4s)/(-4) = (-52)/(-4)\\s = 13`

Putting s=13 in equation 1

`4m+2(13) =86\\4m+26 = 86\\4m = 86-26\\4m = 60\\(4m)/(4) = (60)/(4)\\m = 15`

Hence,

There are 15 carbs in one glass of milk and 13 carbs in one snack bar.