Answer:
55% of the round-trip
Step-by-step explanation:
A technician makes a round-trip to and from a certain service center by the same route means 100% of the trip
the technician completes the drive to the center means half of the trip 50%
then completes 10 percent of the drive from the center means 10% of the 50%
so in total he completes
50 + 50*0.10
50 + 5
55 %
Therefore, the technician has completed 55% of the round-trip.