(i) Let initially the edge of the cube be l. Initial surface area = 6l^{2}

If each edge of the cube is doubled, then it becomes 2l.

New surface area = 6(2l)^{2} = 24l^{2} = 4 × 6l^{2}

Clearly, the surface area will be increased by 4 times.

(ii) Initial volume of the cube = l^{3}

When each edge of the cube is doubled, it becomes 2l.

New volume = (2l)^{3} = 8l^{3} = 8 × l^{3}

Clearly, the volume of the cube will be increased by 8 times.