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 80 percent of the drive from the center, what percent of the round-trip has the technician completed?  Choose the correct option:
A) 50
B) 60
C) 70
D) 80
E) 90
round trip means 2 trips i.e.to and fro. He has completed one i.e 50% completed. then he traveled another 80% of 50% i.e 40%. so he completed   50 +40= 
<gadget id="calculator">  50 +40</gadget>
<output>90</output>
90 % of total trip.   90
<result>E</result>
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 80 percent of the drive from the center, what percent of the round-trip has the technician completed?