Question

Starting at home, Michael traveled uphill to the gift store for 24 minutes at just 10 mph. He then traveled back home along the same path downhill at a speed of 30 mph.What is his average speed for the entire trip from home to the gift store and back?

Answer 1

We can figure out how long Michael's trip took by realizing that 30 mph is 3 times 10 mph.  Because of this, the trip home will take 1/3 the amount of time it took to go up the hill.  This makes the equation 24 + 8 = 32 minutes for the whole trip.

Now we need to figure out how long the trip was.  We can do this by multiplying 10 minutes by 24/60, which equals 4.  This means that Michael went 4 miles there, and 4 miles back.  So Michael went a total of 8 miles.

Now we know that Michael went 8 miles in 32 minutes.  Now, we multiply 8 by 60/32.  This gives us 15, so Michael went 15 miles per hour on average in the trip.