combination of these numbers would sum

I have a list of say 20 numbers. The total sum could be anything - i need to find a certain sum using an unknown combination of the numbers. How would I do that?

Ex:
($422.00)
($1,191.39)
($391.13)
($510.00)
($96.35)
($1,931.00)
($504.00)
($738.27)
($2,604.38)
($1,728.99)
($9,247.20)
($43.00)
($5,695.46)
($1,191.39)
($5,614.24)
($1,365.00)
($504.00)
($1,709.82)
($8,088.88)
($16.22)
($59.50)
($9,282.40)

What combination of these numbers would sum to ($7,921.29)?

hi,

I don't have knowledge to offer a sound solution, but I know that this can be referred to as a "knapsack problem" so you may find something useful if you include the phrase as a search term.

The below link shows a similar problem but with more possible numbers that was used as a challenge of the month on an Excel website. The massive thread includes a number of approaches, but from memory the winning result isn't actually published in the thread (I think it is elsewhere on the website though)...
http://www.mrexcel.com/forum/showthread.php?t=16533

Sorry I can't be of more help, maybe one of the more knowledgeable members can...
Rob

heres how its done
i got this from ozgrid some way back
once solver is run the values in col b corresponding to the 1's in col c
will give your total

This is Tushar Mehta's solution:

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Running with your data gave this result:

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