C is 0, since only multiplied by 0 will get 0, and the question defined that a and b not 0, so only c is 0
$150 because the supply number is equivalent to the demand number
Let there be x quarts of the 20% salt solution, and (25 - x) quarts of the 80% salt solution.
Then the total amount of salt in the 20% portion would be 0.2x, while that from the 80% portion would be (0.8)(25 - x). This would have to total up to (0.44)(25) in the final solution, so the equation is:
0.2x + 0.8(25 - x) = (0.44)(25)
-0.6x + 20 = 11
x = 15 quarts of the 20% salt solution
25 - x = 10 quarts of the 80% salt solution
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
