AboutSurajit Basu Expertise I can answer questions which are mathematical, logical, or wordplay related.
I am not good at highly creative problems, or riddles.
Experience I regularly do puzzles, and help out friends, teenagers. I read books written by Martin Gardener. I love the puzzles and Easter eggs in Douglas Hofstadter's Godel, Escher, Bach: an enternal golden braid.
Publications A few examples of my writing:
http://surajitbasu.sulekha.com/blog/post/2006/04/the-journey-down-the-number-line.htm
Education/Credentials B. Tech. ( Computer Science), IIT Kanpur, India
MBA ( Post-Graduate Diploma in Business Management), (Finance, Systems), IIM Calcutta, India
Question you have a scale of justice and eight balls. seven balls weigh the same and one is heavier. you can not tell the heavier ball by holding it. if you can only use the scale twice. how do you determine the heavier ball?
Answer take any three on one side; three others on the other side.
There are two possibilities: A and B.
A) If both are equal, then the remaining two contain the heavier ball.
Just weigh these two, the heavier one is it.
B) If one side is heavier, then that set of three contains the heavier ball.
Just weigh two of these three; if one side is heaver, the heavier one is it. If both are equal, the remaining one is it.
now, two questions:
what if you have 9 balls? can you do it in 2 weighings?
what if you have 12 balls? can you do it in 3 weighings?
