<PRE><B>Question 61518</B>
let the flying time of the plane be x m.p.h.
we know that distance /speed = time
the plane travels 560 miles in the first part of the journey
the plane travels 480 miles in the second part of the trip     the plane takes one hour longer for the the 1st part of the journey
we have 560/x - 480/x=1
multiplying both sides by x we get
560 -480 =x
x = 560 -480
    80
speed of the plane is 80 m.p.h.
time taken for the 2nd portion of the trip is 
480/80
=6 hours 
the answer is 6 hrs.
good luck !!!</PRE>