NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 12: Surface Areas & Volumes - Exercise 12.1
Question 8

Question.  8

A hollow cube of internal edge 22 cm is filled with spherical marbles of diameter 0.5 cm. If \(\dfrac{1}{8}\) of the space remains unfilled, then the number of marbles the cube can accommodate is

(A)

142296

(B)

142396

(C)

142496

(D)

142596

Detailed Answer with Explanation:

Step 1: Find the volume of the cube.

The internal edge of the cube = 22 cm.

Volume of cube = \(a^3 = 22^3 = 10648\,\text{cm}^3\).

Step 2: Account for the empty space.

Only \(\tfrac{7}{8}\) of the cube is filled with marbles.

Filled volume = \(\tfrac{7}{8} \times 10648 = 9317\,\text{cm}^3\).

Step 3: Find the volume of one marble.

Diameter of one marble = 0.5 cm, so radius = 0.25 cm.

Volume of one sphere = \(\tfrac{4}{3}\pi r^3 = \tfrac{4}{3}\pi (0.25)^3\).

= \(\tfrac{4}{3}\pi (0.015625) = 0.020833\pi \approx 0.06545\,\text{cm}^3\).

Step 4: Find the number of marbles.

Total filled volume ÷ Volume of one marble = \(\tfrac{9317}{0.06545}\).

≈ 142396 marbles.

Final Answer: Option B (142396)

NCERT Exemplar Solutions Class 10 – Mathematics – CHAPTER 12: Surface Areas & Volumes – Exercise 12.1 | Detailed Answers