Before and After (Posted on 2004-07-23)

	Submitted by Federico Kereki
Rating: 4.5000 (4 votes)
Solution:	(Hide)
This kind of sequence is called a Farey series, and given two fractions (a/b, c/d) in sequence, they satisfy bc-ad=1. If a/b=11/21, then 11b-21a=1, and a and b should be as large as possible but less than 99, which works out to 45/86. For the other side you find 43/82.

	Subject	Author	Date
	same ans as Charlie - w ineff c prog	vectorboy	2004-07-23 16:35:26
	Similar Problem	Gamer	2004-07-23 12:30:22
	computer solution	Charlie	2004-07-23 11:19:08
	Starting idea	Larry	2004-07-23 10:19:03