How many lead shots each 3 mm in diameter can be made from a cuboid of dimensions 9 cm × 11 cm × 12 cm ?

Answer: Option D

Volume of each lead shot :
$$\begin{array}{rl}& =\left[\frac{4}{3}\pi \times {\left(\frac{0.3}{2}\right)}^3\right]\text{ c}{\text{m}}^3\\ & =\left(\frac{4}{3}\times \frac{22}{7}\times \frac{27}{8000}\right)\text{ c}{\text{m}}^3\\ & =\frac{99}{7000}\text{ c}{\text{m}}^3\end{array}$$
∴ Number of lead shots :
$$\begin{array}{rl}& =\left(9\times 11\times 12\times \frac{7000}{99}\right)\\ & =84000\end{array}$$