How many spherical bullets of radius 7 cm can be made out from a cube of lead whose edge is 77 cm?

317

Volume of cube = Total volume of all spherical bullets

⇒ (side)³ = n × \(\frac{4}{3}\) \(\pi \)r³

⇒ (77)³ = n × \(\frac{4}{3}\) \(\pi \) × 7³

⇒ (7)³ × (11)³ = n × \(\frac{4}{3}\) × \(\frac{22}{7}\) × 7³

⇒ \(\frac{11 × 11 × 11 × 3 × 7}{22 × 4}\)

⇒ n = 317