Answer:
875
Explanation:
215+200+185+170+155+140+125+110+95+80+65+50+35+20+5+(-10)+(-25)+(-40)+(-55)+(-70)+(-85)+(-100)+(-115)+(-130)+(-145) =875
I'm sure there's an easier way to do this, but if you want a correct answer, here you go. Have a good day!