David walks to a viewpoint and returns to the starting point by his car and thus takes a total time of 4 hours 20 minutes. He would have gained 2 hours by driving both ways. How long would it have taken for him to walk both ways.  Choose the correct answer
A) 5 h 20 min B) 4 h 15 min C) 6 h D) 7 h E) 6 h 20 min
1.Walking to to a viewpoint+Driving back=4 hours 20 minutes   2.Driving to a viewpoint+Driving back=4 hours 20 minutes - 2 hours=2 hours 20 minutes, thereforeone way driving=2 hours 20 minutes/2 =1 hours 10 minutes.   3. From 1.one way driving=4 hours 20 minutes-1 hours 10 minutes=3 hours 10 minutes.   4.Walking to to a viewpoint+Walking back=3 hours 10 minutes+3 hours 10 minutes=6 hours 20 minutes.   Answer: 6 h 20 min
<result>E</result>
David walks to a viewpoint and returns to the starting point by his car and thus takes a total time of 4 hours 20 minutes. He would have gained 2 hours by driving both ways. How long would it have taken for him to walk both ways.