410.3ft^3. is correct
volume of the sphere with 3ft radius :
[tex] \frac{4 \times \pi \times 3 \times 3 \times 3}{3} = 113[/tex]
volume of the sphere with 5ft radius:
[tex] \frac{4 \times \pi \times 5 \times 5 \times 5}{3} = \frac{1570}{3} = 523.3[/tex]
difference
[tex]523.3 - 113 = 410.3[/tex]
good luck
