The difference between 1/8 and 6/10 = 0.475 , does this help?
9y^3+8y=4y+18y^2
9y^3-18y^2+4y=0
*Divide the whole thing by y
9y^2-18y+4=0
*use quadratic formula to solve
400/2 = 200
200 + 20 = 220
200 - 20 = 180
Answer: He had gone 220 miles.
He was 180 miles from the finish and 220 from the start, so he was 40 miles closer to the finish than to the start.