2.
You will have on real root, and two complex which derives from the 3rd degree polynomial function.
16.79+28.49=45.28
50-45.28=4.72
Kelly would get $4.75 back
Since 
(density = mass/volume), we can get the mass/weight of the liquid by integrating the density 
over the interior of the tank. This is done with the integral
which is more readily computed in cylindrical coordinates as
Rocky ate 42 cups of dog food. Since there are 7 days in a week, 21 cups were eaten per week (3x7). Since the question is asking for the amount in two weeks, you multiply 21x2 to get 42.
