Answer: there are 11 calories in one glass of milk and 14 calories in one snack bar.
Step-by-step explanation:
Take milk to to be M and snack bars to be S.
Use algebra, so
2m + 3s = 64 and also
4m + 2s = 72
Multiply the top equation by 2 so both have 4m, so
4m + 6s = 128 and also
4m + 2s = 72
Then minus the numbers form the top equation by the bottom equation, so
4m + 6s = 128
- - -
4m + 2s = 72
This gives you 4s=56 so divide by 4 so s=14
No put 14 into the equation for s and rearrange to solve for m, so
2m+3s=64 So
2m+3x14=64
2m+42=64
Then minus 42
2m=22
m=11