Its a reflection because the image flips along the line of symmetry.
The shape of the water is that of a "spherical cap." The formula for the volume of a spherical cap is ...
... V = π·h²·(r -h/3) . . . . . . . from web search
For a radius of 5 in, this is
... V = π·h²·(5 -h/3) . . . . in³
_____
For h=0
... V = π·0²·(5 -0/3) = 0
For h=5 in
... V = π·(5 in)²·((5 -5/3) in) = (2/3)π·5³ in³ . . . . . the volume of a hemisphere of radius 5
Jim goes to the shop and sees that the T-shirts are only $5.75 each and so wishes to buy 3 of them.
Expressed as a fraction $5.75 = $5 3/4
How much does he have to pay?
The answer is $17.25 or 17 1/4
Can you include pictures?