Answer:Displacement =69 km
Step-by-step explanation:
Given
First John notices 245 km marker i.e. he is 245 away from destination.
John travels until he reach 135 km marker i.e. he is 135 km away from destination.
After that he retraces his path to reach 176 km marker
so his resultant displacement is i.e. shortest distance between initial and final point is 245-176 =69 km