Question 1031906
Convert to minutes:
 3*60 = 180 minutes
 and 600/400 = 1.5 It takes 1.5 times longer coming back
 x+1.5x= 180
 2.5x = 180
 x = 72 minutes is the fast speed
 and
 72*1.5 = 108 is the fast speed
 72+108=180 minutes and 180/60 = 3 hours of flight total.