Answer:
it's -10
Step-by-step explanation:
18+ (-10)= 8
Piper traveled 115 miles for 6 hours.
We just add the amount of distance that Piper traveled together, so "55+60 = 115 miles" and then we add the amount of time it took to travel that distance. So "3.5 + 2.5 = 6 hours".