Answer:
15.6 m
Explanation:
I'm pretty sure that there is supposed to be a t to the right of the (7.5 m/s).
If we substitute t with 0 (s), we get X1 = -6.0 m and X2 = 9.6 m.
The distance between the bicycles is X2-X1.
9.6 m -(-6.0 m)
= 9.6 m + 6.0 m
= 15.6 m
Hope this helps!