Question 4
There are 165 unit cubes arranged in 5 square layers with no space between the cubes as shown. The layers are 1 by 1, 3 by 3, 5 by 5, 7 by 7, and 9 by 9. If a sixth layer is placed on the bottom of the arrangement following the pattern, how many unit cubes are completely surrounded by six other unit cubes?
Follow the centred, aligned square-layer arrangement shown; “surrounded” means sharing each of the six faces with a neighbouring cube.
Choose one letter A–E.
Follow the centred, aligned square-layer arrangement shown; “surrounded” means sharing each of the six faces with a neighbouring cube.
Choose one letter A–E.