How many hollow spheres having inner radius of 1 cm can be completely filled by transferring water from a completely filled hollow sphere having inner diameter of 20 cm?

Correct option is C

Formula:
Volume of a sphere = (4/3) × π × r³
Number of smaller spheres = Volume of large sphere ÷ Volume of one small sphere
Solution:
Inner diameter of large sphere = 20 cm → Radius = 10 cm
Inner radius of small sphere = 1 cm
Volume of large sphere
​$$\begin{aligned}&\text{Volume of large sphere} \\&= \frac{4}{3} \pi (10)^3 \\&= \frac{4}{3} \pi \cdot 1000 \\&= \frac{4000}{3} \pi \\\\&\text{Volume of one small sphere} \\&= \frac{4}{3} \pi (1)^3 \\&= \frac{4}{3} \pi \\\\&\text{Number of small spheres} \\&= \frac{\frac{4000}{3} \pi}{\frac{4}{3} \pi} \\&= \frac{4000}{3} \div \frac{4}{3} \\&= \frac{4000}{4} = 1000\end{aligned}$$​​
Final Answer: (c) 1000
Required number of hollow sphere of radius 1 cm is 1000.