Mensuration
Latest Oldest Page: 1 of 1
2

Q. A solid cube with a volume of 13824cm3 is cut into eight cubes of the same volume. The ratio of the surface area of the original cube and the total sum of the surface area of three smaller cubes will be:

  • (A). 2 : 3
  • (B). 2 : 1
  • (C). 4 : 3
  • (D). 8 : 3
Option (C) is Correct

Edge of the original cube = 138241/3 = 24
Surface area of the original cube = 6(24)2 = 6 * 576 = 3456cm2
Now the larger cube is cut into 8 smaller cubes means,
It will be bisected along with its height, breadth, and length.
so, the edge of the smaller cubes will be half of the larger cube.
Now, Volume of one smaller cube = 123 = 1728
Since the larger cube is divided into 8 equal parts so the volume of each part = 13824/8 = 1728
now, the edge of one smaller cube = 17281/3 = 12cm
Total surface area of three smaller cubes
= 3 * 6 * 122
= 18 * 144
= 2592
Required ratio = 3456 : 2592 = 4 : 3