Volume and Surface Area - General Aptitude

Each of the questions given below consists of a statement and / or a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statement(s) is / are sufficient to answer the given question. Read the both statements and
  • Give answer (A) if the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.
  • Give answer (B) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question.
  • Give answer (C) if the data either in Statement I or in Statement II alone are sufficient to answer the question.
  • Give answer (D) if the data even in both Statements I and II together are not sufficient to answer the question.
  • Give answer(E) if the data in both Statements I and II together are necessary to answer the question.
Q1:

What is the volume of a cube?
I.  The area of each face of the cube is 64 square metres.
 II.  The length of one side of the cube is 8 metres.

A I alone sufficient while II alone not sufficient to answer

B II alone sufficient while I alone not sufficient to answer

C Either I or II alone sufficient to answer

D Both I and II are not sufficient to answer

E Both I and II are necessary to answer

ANS:D - Both I and II are not sufficient to answer

Let each edge be a metres. Then, I. a2 = 64       a = 8 m        Volume = (8 x 8 x 8) m3 = 512 m3. Thus, I alone gives the answer. II. a = 8 m        Volume = (8 x 8 x 8) m3 = 512 m3. Thus, II alone gives the answer.  Correct answer is (C).