A sphere and a cube are of the same height. The ratio of their volumes is 3:4            (b)   21:11         (c)  4:3         (d)  11:21

Explanation

The sphere will have the diameter equal to the side of the cube as they are of the same height.
If the length of the side of the cube is a, then the diameter of the sphere` =a` unit
Radius of the sphere `=a/2`
Volume of sphere of radius `r=4/3pir^3`
Hence volume of the sphere `=4/3xxpixx(a/2)^3=(pia^3)/6`
Volume of cube of edge `a=a^3`
Ration of their volume`=(pia^3)/6:a^3=pi/6:1`
`22/7xx6:1=11:21`
So option D is correct.

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