60a^5 is the answer to your question
Neptune is about four times wider than Earth.
We need to get the limits first. When y = 0
0 = 64x - 8x^2
x = 0 and x = 8
The volume is
V = ∫ y dx from 0 to 8
V = ∫ (64x - 8x^2) dx from 0 to 8
V = 32x^2 - 8x^3/3 from 0 to 8
V = 682.67<span />
Here are the calculations for Super Sport:
[12 ($72.50 x 0.8)] 1.065 = $741.24
Here is the math for Double Dribbles:
[12($54.75 x 1.09)] + (12 x $5.99) = $788.01
$788.01 - $741.24 = $46.77
The difference in price is $46.77.