In this case, since the possibilities are fairly small, you can solve this pretty quickly anyways. I wrote a very naive algorithm in ruby and it solved it it in

In this case, since the possibilities are fairly small, you can solve this pretty quickly anyways. I wrote a very naive algorithm in ruby and it solved it it in 7 seconds. # Initialize it with the most we can need of any individual numbers, plus the maximum possible zero's we could use # (Just picked 5, because it can't take more than 7, and we have at least 2 of everything. I know there are better ways of doing this, but I was just hacking something up quickly). x = [2.15,2.75,3.35,3.55,4.2,5.8].map{|n| [n]*(15.05/n).to_i}.flatten + [0]*5 # Find all of the combinations that add up to 15.05 x.combination(7).select{|c| c.inject(:+)==15.05}.uniq There are two answers to this. [2.15,2.15,2.15,2.15,2.15,2.15,2.15] [2.15,3.55,3.55,5.80]