Mary = (1/3)x
Erin = x - 8
John = x
Here is your equation:
(1/3)x + (x - 8) + x = 267
Take it from here.
Answer:
The answer is "789.03 and 806.16".
Step-by-step explanation:

For point a:
Calculating the value for

For point b:
Calculating the value of 
Answer:
1/6 cup of milk
Step-by-step explanation:
1/2 (amount of milk)- 1/3 (amount of water)
1/2 = 3/6
1/3 = 2/6
3/6 - 2/6 = 1/6
Hope this helped <3