Survo puzzles: www.survo.fi/puzzles --------------------------------------- Copyright (c) Survo Systems 2006-2013 The easiest way to solve these three problems may be using a Java Applet http://www.survo.fi/swap/puzzles.html based on the swapping method. Survo puzzle 309/2013 (400) #443-78334 A B C D 1 * 10 * * 55 2 * * * * 25 3 * * * * 45 4 * * * * 11 42 25 37 32 Survo puzzle 310/2013 (400) #443-32258 A B C D 1 * * * * 25 2 * * * * 30 3 14 * * * 36 4 * * * * 45 55 23 45 13 Survo puzzle 311/2013 (460) #443-22760 A B C D 1 * * 3 * 19 2 * * * * 37 3 * * * * 28 4 * * * * 52 52 41 26 17