2 linear regression lines - related?

[gypsyeyes]

Hello,
I am stuck with a problem and I hope someone can help me, Ive explained and diagrammed it in an Excel file which I can email. I cant attach it because it wont let me.
Thank you in advance for any help!
Gypsy

[quark]

I modified attachment permissions. You should be able to upload the Excel spreadsheet now.