Infosys Company Numerical Ability Permutation and Combination

A cube is painted black. It is divided into 125 equal cubes. Find the number of cubes, which have at least 2 sides painted black?

Read Solution (Total 2)

we have to subtrace 2 from every edge and hence the formulae is (n-2) * 12
Here has it is given 125 means (5 * 5 * 5) hence n=2 i.e 3 * 12 = 36
Atleast 2 blacks means 2 or more blacks hence ==> 36 + 8 = 44 (answer)
12 years agoHelpfull: Yes(5) No(0)

answer is 44 because, after dividing into 125 equal cubes
there exist 8 cubes, one at each corner of the cube, will have 3 faces black.
3 cubes along each edge of the cube will have 2 faces black. So, there are 12 such edges & hence 12*3=36 cubes have 2 faces black.
So total no of cubes having at least 2 faces black is 8+36 = 44
6 years agoHelpfull: Yes(1) No(0)

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