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A block of wood in the form of a cuboid 5" × 10" × 13" has all its six faces painted pink. If the wooden block is cut into 650 cubes of 1" × 1" × 1", how many of these would have pink paint on them?
Answer: 386
**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 3" × 8" × 11", and will contain 264 cubes.
Out of a total of 650 cubes, there are 264 cubes without any pink paint on them. Therefore, the remaining 386 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 *a*^{3} − (*a* − 2)^{3}?
Try the Quiz : __Puzzles & Brain Teasers : The Pink Wooden Block__
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