If you walk up a hill at 2 mph and walk down at 3mph what is your average speed?!
Question: 2.4mph (not 2.5mph - this is wrong.)
You don't just average the 2 speeds. The math doesn't work that way.
EXPLANATION:
Let total distance walked = 2m miles
Then time to walk up hill is: t1 = distance / speed = m / 2
And time to walk down hill is: t2 = m / 3
So total time is: t1 + t2 = m/2 + m/3.
And average speed = total distance / total time =
2m / (m/2 + m/3) = 2.4 miles per hour.
(Note: the m's cancel so they don't appear in the answer.)
EXAMPLE:
If it's 6 miles up the hill and 6 miles back down again then:
Total distance = 12 miles
Time to walk up hill = 3 hours
Time to walk down hill = 2 hours
Average speed = Overall distance / Overall time = 12 / (3 + 2) = 12 / 5 = 2.4 mph.
Answers: 2.4mph (not 2.5mph - this is wrong.)
You don't just average the 2 speeds. The math doesn't work that way.
EXPLANATION:
Let total distance walked = 2m miles
Then time to walk up hill is: t1 = distance / speed = m / 2
And time to walk down hill is: t2 = m / 3
So total time is: t1 + t2 = m/2 + m/3.
And average speed = total distance / total time =
2m / (m/2 + m/3) = 2.4 miles per hour.
(Note: the m's cancel so they don't appear in the answer.)
EXAMPLE:
If it's 6 miles up the hill and 6 miles back down again then:
Total distance = 12 miles
Time to walk up hill = 3 hours
Time to walk down hill = 2 hours
Average speed = Overall distance / Overall time = 12 / (3 + 2) = 12 / 5 = 2.4 mph.
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