Total Distance = x
Luis walked one-eighth of x = x(1/8) = x/8
He still need to walk = Total Distance - Distance covered
He still need to walk = x-x/8
He still need to walk = (8x-x)/8
He still need to walk = 7x/8
He still need to walk = x(7/8)
He still need to walk seven-eighth of the total distance.
