sales margin question

Hi,

I can't get my head round the following sales margin split, can someone please help?

2 people have agreed to split the margin on a sale and both will contribute to expense costs although these costs have all be paid by person 1 up front.

So the overall sales margin is $3500 and person 1 has spent $800 on expenses.

How much is each person entitled to claim?

Thanks in advance
Paul

What are the total expenses?

Total expenses are $800, all paid by person 1.