Answer:
 523.6 km
Step-by-step explanation:
Let x represent the distance traveled by train. Then 1020-x is the distance traveled by bus. The travel times are given by the relation ...
 time = distance/speed
Then the total travel time in hours is ...
 x/160 +(1020-x)/105 = 8
 21x +32640 -32x = 26880 . . . . .  multiply by 3360
 5760 = 11x . . . . . . . . . add 11x -26880
 523.6 ≈ x . . . . . . . . . . divide by 11
Aidan traveled about 523.6 km by train.