Multiple choice

How many spherical bullets can be made out of a lead cylinder $15$cm high and with base radius $3$cm, each bullet being $5$mm in diameter?

  1. $6000$
  2. $6480$
  3. $7260$
  4. $7800$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume of cylinder = pi * r^2 * h = pi * 3^2 * 15 = 135 * pi. Volume of spherical bullet (radius = 0.25 cm) = (4/3) * pi * (0.25)^3 = (4/3) * pi * (1/64) = pi / 48. Number of bullets = (135 * pi) / (pi / 48) = 135 * 48 = 6480.

AI explanation

The volume of the lead cylinder is pi times 3 squared times 15, yielding 135 pi cubic cm. The volume of one spherical bullet with a radius of 0.25 cm is 4 over 3 pi times 0.25 cubed, which is one over 48 pi cubic cm. Dividing 135 pi by one over 48 pi gives 6480 bullets.

Keep practicing — related questions