Direction: 343 Small unpainted cubes are arranged to from a large cube. All the six faces of the large cube are painted white. Now, a 3 x 3 cube, comprising 27 small cubes, is removed out from one of the corners of the large cube. The 3 x 3 cubes is now painted blue on all six faces, while all the three surface (each of which a is a 3 x 3 square) of the large cube exposed due to the removal of the 3 x 3 cube are painted black. Then, the 3 x 3 cube is put back in its original position in the large cube and the large cube is finally painted yellow on all the six faces.
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How many cubes are painted with yellow and blue?
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- 12
- 18
- 15
- 14
Correct Option: C
Initial total number of cubes = 343,
Number of cubes removed = 27
Smaller 27 cubes painted blue
Exposed faces of original big cube (3 faces with 9 cube on each face i.e total 27 cubes) painted with black
Out of 27 small cubes from 3 x 3 x 3, outer 26 cubes are 1st painted with blue and then it is kept back with original cube and painted with yellow so out of 26 cubes only 5 edges will give us cubes with both the colours and number of such cubes are 12
