Here's what I'm not understanding...

If Francois pays out $750, then he owes $1,500. ($750 is 50% of $1,500).

If Pierre pays out $250, then he owes $2,500. ($250 is 10% of $2,500).

Together, Francois and Pierre pay out a total of $1,000. However, they owe Claudine a total of $4,000 ($1,500 + $2,500). $1,000 is not 40% of $4,000.

Now, if you use $750 for Francois and only $50 for Pierre, the math works out as follows:

Total Payment = 750 + 50 = 800

Total Owed = 1500 + 500 = 2000

And $800 is 40% of $2,000.

Could someone PLEASE shed some light. I've been tinkering over this problem for the past hour.