Question

Q19. The percentage increase in the surface area of a cube when each side is
increased to 3/2 times the original length is *
0 225
325
0425
O 125
Q20. *
The radius and height of a cone are each increased by 20%, then the volume of the cone is increased by​

Answer 1

Let side of the cube be x. 

Then its total surface area =6x2.

If each side is increased to 23x

Total surface area =6×23x×23x=227x2

∴ Increase =227x2−6x2=215x2

∴ % increase =215x2×6x2100=125