Question 566220
Maria drove to a business appointment at 50mph in the morning.  Her average speed on the return trip in the afternoon was 40 mph. The return trip took 1/4hr longer because of traffic. How far did she travel to the appointment?
------------------
d = r*t
d = 50t = 40*(t + 0.25)
50t = 40t + 10
t = 1 hour
--------------
d = 50*1 = 50 miles
==================
Notice that the avg speed for the round trip is not the average of 50 and 40.
Why is that?
The avg speed is less, = 44.444... mi/hr, not 45