I think it is the first one.
Mean the the total of all values, divided by the number of values
3/3-1/3= 2/3 of the glasses
Answer:

Step-by-step explanation:
Let
x -----> the number of minutes
y ----> the balloon's height in feet
we know that
The linear equation in slope intercept form is equal to

where
m is the slope
b is the y-coordinate of the y-intercept
In this problem we have that
The slope is equal to
----> is negative because is a decreasing function

Remember that the y-intercept is the value of y when the value of x is equal to zero
In this context the y-intercept is the height of the balloon when the time is equal to zero (initial height)
substitute

From the equation of motion, we know,

Where s= displacement
u= initial velocity
a= gravitational force
t= time
Displacement is 0 since the ball comes back to the same point from where it was thrown.
A =
since the ball is thrown upwards.
Plug the known values into the equation.
=> 
Solving for u gives :
u= 16.67 m/ sec ....... equation (1)
At maximum height, final velocity i.e v is 0
Time take to reach the top = 

=> 
Solving for s we get
s= 14.16 m