Target Exam

CUET

Subject

General Aptitude Test

Chapter

Quantitative Reasoning

Topic

Mensuration: 2D/3D

Question:

Which of the following statements are true?

(A) If the diagonal of a cube is $6\sqrt{3} cm$, then its volume and surface area are equal.
(B) If a rectangular block having dimensions 6 cm × 12 cm × 15 cm is cut into an exact number of equal cubes, then the least possible number of such cubes is 27.

Choose the correct answer from the options given below:

Options:

(A) only

(B) only

Both (A) and (B)

Neither (A) nor (B)

Correct Answer:

(A) only

Explanation:

The correct answer is Option (1) → (A) only

Let us verify each statement.

Statement (A)

Diagonal of a cube $= a\sqrt{3}$​

Given:

$a\sqrt{3} = 6\sqrt{3} \Rightarrow a = 6 \text{ cm}$

  • Volume $= a^3 = 6^3 = 216$
  • Surface area $= 6a^2 = 6 \times 36 = 216$

Volume = Surface area
Statement (A) is true

Statement (B)

Dimensions of cuboid = $6 \times 12 \times 15$

Side of largest possible cube = HCF of $6,12,15=3$ cm

Number of cubes:

$\frac{6}{3} \times \frac{12}{3} \times \frac{15}{3} = 2 \times 4 \times 5 = 40$

Least possible number of cubes = 40, not 27.

Statement (B) is false

Correct Answer: (A) only