UPSC Prelims 2010 · General Studies
Question 6: Logical Reasoning and Mental Ability
A cuboid has six sides of different colours. The red side is opposite to black. The blue side is adjacent to white. The brown side is adjacent to blue. The red side is face down. Which one of the following would be opposite to brown ?
AnswerThe answer is (c).
Red is opposite black, and red is face down, so black is on top. The four side faces are blue, white, brown and one colour not named. Blue is adjacent to white, so blue is not opposite white. Brown is adjacent to blue, so brown is not opposite blue. Blue therefore faces the unnamed colour, which leaves white opposite brown. Remember: adjacent faces can never be opposite; eliminate until one pair is left.
Why each option is right or wrong
- (a) Red is opposite black, as given.
- (b) Black is opposite red, as given.
- (c) Right: blue must face the unnamed colour, so white and brown face each other.
- (d) Brown is adjacent to blue, so they cannot be opposite.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2010, General Studies, Series A. The paper on upsc.gov.in.