Question

Two glasses of milk and 3 snack bars have a total of 68 carbs, and 4 glasses of milk and 2 snack bars have a total of 80 carbs. Determine how many carbs are in one glass of milk and in one snack bar.

Answer 1

Amount of carbs in one glass of milk is 13 and amount of carbs in one snack bar is 14

Solution:

Let "m" be the amount of carbs in one glass of milk

Let "s" be the amount of carbs in one snack bar

Given that two glasses of milk and 3 snack bars have a total of 68 carbs

carbs in one glass of milk x two glasses of milk + carbs in one snack bar x 3 snack bars = 68 carbs

2m + 3s = 68 ---- eqn 1

Similarly,

Also given that 4 glasses of milk and 2 snack bars have a total of 80 carbs

4m + 2s = 80 ------ eqn 2

Let us solve these two equations and find values of "m" and "s"

Multiply eqn 1 by 2

4m + 6s = 136 --- eqn 3

Subtract eqn 2 from eqn 3

4m + 6s = 136

4m + 2s = 80

(-) ----------------------

4s = 56

s = 14

Substitute s = 14 in eqn 1

2m + 3s = 68

2m + 3(14) = 68

2m = 26

m = 13

Thus the amount of carbs in one glass of milk is 13 and amount of carbs in one snack bar is 14