Buying Books (Posted on 2002-05-16)

	Submitted by Half-Mad
Rating: 3.6000 (10 votes)
Solution:	(Hide)
For each father-son couple holds: the father bought x books for x shillings each, the son bought y books for y shillings each. The difference between their expenses is 21 shillings, thus x^2 - y^2 = 21. Since x and y are whole numbers (each book costs a whole amount of shillings), there are two possible solutions: (x=5, y=2) or (x=11, y=10). Because the difference between Alex and Peter is 5 books, this means that father Alex bought 5 books and son Peter 10. This means that the other son, Tim, bought 2 books, and that his father is Alex.

	Subject	Author	Date
	No Subject	Cassandra Michael	2024-07-19 05:37:19
	Solution	Dej Mar	2008-06-04 16:21:14
	Puzzle Solution	K Sengupta	2008-06-04 00:45:01
	answer	K Sengupta	2007-11-17 05:16:38
	each of them?	john	2005-03-11 19:10:51
	re: Answer	john	2005-03-11 18:51:52
	re: Tim	john	2005-03-11 18:48:56
	none	Lee	2003-09-15 02:44:35
	Answer	Julie	2003-09-14 22:57:38
	Tim	Tim Axoy	2003-03-21 12:20:25
	the answer	kristina	2002-09-07 15:14:35
	Algebra	TomM	2002-05-16 16:37:29
	First Thoughts (for real)	TomM	2002-05-16 16:20:01
	First thoughts	TomM	2002-05-16 16:03:55