Question 501107: You drive 20 miles at 55 mph, then 5 miles at 40 mph and finally, 2 miles at 25 mph. What is your average speed for this trip? Answer by ptaylor(2198) (Show Source):
You can put this solution on YOUR website! Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r
also
Average speed =(total distance)/(total time)
Total distance=20+5+2=27 miles
Time traveling at 55 mph=20/55=4/11 hr
Time travelling at 40 mph=5/40=1/8 hr
Time traveling at 25 mph=2/25 hr
Total time=4/11 +1/8 + 2/25=0.364 +0.125+0.08=0.569 hr
Average speed=27/0.569=47.452 mph
Hope this helps----ptaylor
