Multiple choice general knowledge math & puzzles

A block of wood in the form of a cuboid 3" × 9" × 12" has all its six faces painted pink. If the wooden block is cut into 324 cubes of 1" × 1" × 1", how many of these would have pink paint on them?

  1. 324

  2. 321

  3. 307

  4. 290

  5. 254

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

A 3×9×12 cuboid has 324 unit cubes. The cubes with paint are those with at least one face on the surface. Unpainted cubes form an inner cuboid of dimensions (3-2)×(9-2)×(12-2) = 1×7×10 = 70 cubes. Painted cubes = 324 - 70 = 254. Option E is correct.