Question 1011283: Tyra averages 40 mi/her driving to the airport during rush hour and 60mi/he on the return trip late at night. What is Tyra's average speed for the entire trip?
Found 2 solutions by josmiceli, solver91311:
Answer by josmiceli(19441)   (Show Source):
Answer by solver91311(24713)  (Show Source):
You can put this solution on YOUR website!
The average rate of speed for an entire trip is the total distance travelled divided by the total travel time. Since neither the distance or total time was given, I have to assume that whoever wrote the problem intended for you to assume that she drove to the airport during rush hour and then when she arrived it was instantaneously late at night and she immediately turned around and drove home, which is to say there was no delay or wait time at the airport. Without this assumption, this problem cannot be solved as presented. You might want to point out to your instructor that story problems are much more instructive if the story actually makes sense in the real world.
The amount of time,  , it takes to go  miles at  is  , and the amount of time,  , it takes to go miles at  is  . This is based on the fact that the distance to the airport is assumed to be the same as the distance home from the airport. Then we can say that the total time,  , is:
Add the two fractions by finding the common denominator:
but the total distance traveled is  , so:
or
And the average speed is then 
John
My calculator said it, I believe it, that settles it
|
|
|
