Question

What will happen to volume of a cube, if its edge is doubled

Answer 1

let side be a
Then volume =a^3
Side doubled=2a
New volume =(2a)^3=8a^3
Hence ratio between new and original volumes =8a^3/a^3=8:1
Hence the volume will become 8 times.

Answer 2

Let the edge of the cube initially be a
volume = a^3

When the edge is doubled,edge becomes 2a
volume = (2a)^3 
             =  8a^3

volume of a cube increases by 8 times when edge is doubled.