Question

How many lead balls, each of radius 1 cm, can be made from a sphere of radius 8 cm?

Answer 1

Radius of the sphere = 8 cm

Volume of the sphere = $\frac{4}{3}\mathrm{\pi }{r}^3=\frac{4}{3}\times \frac{22}{7}\times 8^3=2145.52{\mathrm{cm}}^3$
Radius of one lead ball = 1 cm
Volume of one lead ball = $\frac{4}{3}\times \frac{22}{7}\times 1^3=4.19{\mathrm{cm}}^3$

∴ Number of lead balls = $\frac{\mathrm{volume}\mathrm{of}\mathrm{the}\mathrm{sphere}}{\mathrm{volume}\mathrm{of}\mathrm{one}\mathrm{lead}\mathrm{ball}}=\frac{2145.52}{4.19}=512.05\approx 512$