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Tuesday, April 14, 2015

Solution to Singapore Olympiad P5 question

The most trending question on social networks.. this question has been asked for a 10 year old kid in Singapore. We all know that Singapore primary children have been topping the international Olympiads.. Here's a sample question proving the theory


Detailed Solution:

In the given problem Cheryl says 

  • Month to Albert as May, June, July or August
  • Date to Bernard as 14, 15, 16, 17, 18, 19.

General Inference:
  • 18 and 19 are the unique dates(in terms of numbers)

First Statement inference(by Albert):
  • If the month was May or June, Albert wouldn't be so sure that Bernard doesn't know the answer for sure because of the unique dates 18 and 19

Second Statement inference(by Bernard):
At first Bernard didn't know the answer, later he knew based on the statement of Albert
  • Albert doesn't have May or June
  • If Bernard had 14 with him, he wouldn't have known the answer because 14 is common in July and August also (but he knows the answer now)
  • Bernard had an unique number among 15, 16 or 17 with him to be sure of the answer

Third Statement inference (by Albert):
  • Finally among Dates, its down to 15,16 or 17 and months, its July or August
  • If Albert had August with him, he wouldn't be sure of the answer as he'd not still be sure of 15 or 17 in August (but knows the answer now)
  • It's possible as Albert had July with him and the only date possible in July is July 16

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