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Math Puzzles & Brain Teasers

The Pink Wooden Block

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 Hide all answers   View all answers   Print   Try the Quiz A block of wood in the form of a cuboid 6" × 10" × 11" has all its six faces painted pink. If the wooden block is cut into 660 cubes of 1" × 1" × 1", how many of these would have pink paint on them? Answer: 372 Solution: The 1" × 1" × 1" cubes that do not have any pink paint on them will be at the core of the wooden block. This core will be 4" × 8" × 9", and will contain 288 cubes. Out of a total of 660 cubes, there are 288 cubes without any pink paint on them. Therefore, the remaining 372 cubes will have one, two or three sides with pink paint on them (depending on whether they were at the face, edge or corner of the wooden block). Food for thought: What if the wooden block was in the shape of a cube (a" × a" × a") rather than a cuboid? Can you show that the number of cubes with paint on them is then given by a3 − (a − 2)3?   Try the Quiz :     Puzzles & Brain Teasers : The Pink Wooden Block