A 4 cm cube is cut into 1 cm cubes. What is the percentage increase in the surface area after such cutting?
A. 4%
B. 75%
C. 300%
D. 400%
Volume of 4 cm cube = 64 cc. When it is cut into 1 cm cube, the volume of each of the cubes = 1cc Hence, there will be 64 such cubes. Surface area of small cubes = 6 (12) = 6 sq cm. Therefore, the surface area of 64 such cubes = 64 * 6 = 384 sq cm. The surface area of the large cube = 6(42) = 6*16 = 96. % increase = (384 - 96)/96 = 300%