A truck with a heavy load drove from Boston to New York at 45 mph. After unloading, it returned from New York to Boston at a speed of 65 mph. What was its average speed for the whole trip?
Let distance from New York to Boston, and vice-versa, be D
Then, time taken to travel from Boston to New York is:
Also, time taken to travel from New York to Boston is:
Total time taken for entire trip: ____________
Average speed:
Average speed:
Average speed:
Average speed: ------ Canceling 2D in numerator and denominator
Average speed: , or mph