What is the ratio of volume to surface area for these shapes

-a cube with a side length of 8cm
-a sphere with a radius of 5cm
-a cylinder with a radius of 5 and a height of 7cm

My answers:
4:3
5:3
35:24
Someone please help me

8^3 : 6*8^2 = 8:6 = 4:3

4/3 * 5^3 : 4*5^2 = 5:3
5^2*7 : 2*5^2 + 2*5*7 = 175 : 120 = 35:24