A hollow sphere has an outer radius of 6 cm and an inner radius of 4 cm. If the material used to make the sphere costs ₹10 per cm², what is the total cost of the material used to make the sphere? (Use ₹ ≈ 3.14)
Show answer & explanation
Correct answer: C
Explanation
Outer radius (R) = 6 cm
Inner radius (r) = 4 cm
Cost = ₹10 per cm²
Total surface area = 4π(R² + r²)
= 4 × 3.14 × (36 + 16) = 653.12 cm²
Total cost = 653.12 × 10 = ₹6531.2