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Question

A solid cube of side 7 cm is melted and recast into identical solid spheres each of radius 1 cm. Determine the number of such spheres formed. 

(Take π = 22/7)

This question was previously asked in
UPTET 2026 Paper 2 Social Studies Question Paper (3-Jul-2026) (Shift 1)
The correct answer is

81

The volume of the cube is \(7^3 = 343 \text{ cm}^3\).

The volume of one sphere of radius 1 cm is \(\frac{4}{3}\pi r^3 = \frac{4}{3} \times \frac{22}{7} \times 1^3 = \frac{88}{21} \text{ cm}^3\).

The number of spheres formed is the total volume divided by the volume of one sphere: \(343 \div \frac{88}{21} = \frac{343 \times 21}{88} \approx 81.86\).

Since only whole spheres can be cast from the melted material, this gives the closest matching count of 81 complete spheres.

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