The football is in the box of which colour ?
- (a) Yellow
- (b) Indigo
- (c) Cannot be determined as data are inadequate ✓ UPSC's answer
- (d) Blue
Why the answer is (c)
• Balls known directly: A has tennis, C has cricket, B has volleyball; so hockey, golf and football are in D, E and F.
• Hockey is in neither D nor E, so hockey is in F.
• Golf is not in D, so golf is in E, leaving football in D.
• Colours: A orange, C green; golf is in the violet box, so E is violet.
• Hockey's box (F) is neither blue nor yellow, so F is indigo; B and D share blue and yellow, and nothing decides which is which.
• Football is in D, whose colour is blue or yellow, so it cannot be fixed.
• Hence option (c).
Why the other options are wrong
- (a) Yellow
- D may be yellow or blue, so yellow is not certain.
- (b) Indigo
- Indigo is F's colour, and F holds hockey.
- (d) Blue
- D may be blue or yellow, so blue is not certain.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2016, held on 7 August 2016. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.