Hello everyone, ok, I've spent a little over two hours thinking about this
one, among the other dozen or so formulas I have managed to already solve. I
was wondering if a few other braniac excel geniuses can tag along on this
one. It's basically easy, somewhat, here it goes

With a goal seek, all it would be is Change C by getting R to 15%, it drives
for about 10 seconds and bam, solution.

I need a formula to this for 40 rows instead of running goal seek each time,
Is this possible?

Now 15% is a formula based on the total of Sum(A:Z)/Receipt. Now each
letter through A-Z is dependant on what C has, each cell in A-Z is a formula
that depends on C.

I hope that helps so far.