A technician makes a round-trip to and from a certain service center by the same route. If the technician completes the drive to the center and then completes 10 percent of the drive from the center, what percent of the round-trip has the technician completed?

55% of the round-trip

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.