What is the length of an edge of a cube whose total surface area is X cm2 and whose total surface area is \(\frac{X}{2}\)cm3?

A.

3

B.

6

C.

9

D.

12

Correct answer is A

Total surface area of cube = 6s2

6s2 = x

s2 = x = \(\frac{x}{6}\).....(1)

volume of a cube = s2 = \(\frac{x}{2}\)

s2 = \(\frac{x}{2}\)......(2)

put(1) into (2)

s(\(\frac{x}{6}\)) = \(\frac{x}{2}\)

s = \(\frac{x}{2} \times \frac{6}{x}\)

= 3cm