Take your time if you need to. I need a correct answer

Answer:
6 glasses of water
Step-by-step explanation:
This is fairly simple as we already have the equation
x+y=10 ---> x=10-y
8x+12y=96
now substitute
80 -8y + 12y = 96
4y= 16
y=4
if y = 4
x+4=10
x=6
Mark drank 6 glasses of water