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View Poll Results: Calculate average speed
12 mph 3 4.48%
13.3 mph 48 71.64%
15 mph 13 19.40%
17.67 mph 2 2.99%
something else 1 1.49%
Voters: 67. You may not vote on this poll

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Old 07-07-11, 07:51 PM   #1
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Just for Fun - Calculate Average Speed

Just for FUN, please. Most of you have done this before, others may find it new and perhaps surprising. Anyway, it's time to revisit calculating average speed.

OK - if one goes 10 miles at 20 miles per hour and 10 miles at 10 miles per hour, what is the average speed?

Please check your answer above.

Again, just for FUN

Last edited by DnvrFox; 07-07-11 at 07:55 PM.
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Old 07-07-11, 07:56 PM   #2
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The BF average is 22 mph because they don't count the stops and it was windy.
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Old 07-07-11, 07:57 PM   #3
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The BF average is 22 mph because they don't count the stops and it was windy.
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Old 07-07-11, 08:23 PM   #4
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The BF average is 22 mph because they don't count the stops and it was windy.
...and it was ridden on an old steel bike, and the brakes were rubbing, and the tires weren't properly inflated, and it was too hot, too humid, too cold and too dry all at once (but only in the road forum).
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Old 07-07-11, 08:30 PM   #5
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Is this a SAT test? Do trains still leave Denver @ .....
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Old 07-07-11, 08:33 PM   #6
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Is there a headwind or any hills?
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Old 07-07-11, 08:37 PM   #7
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If you do the math, you will find that if you climb a 5 mile hill slowly, and descend the other side (5 miles) very fast, your average speed is not your speed ascending plus your speed descending, divided by 2.
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Old 07-07-11, 08:41 PM   #8
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If you do the math, you will find that if you climb a 5 mile hill slowly, and descend the other side (5 miles) very fast, your average speed is not your speed ascending plus your speed descending, divided by 2.
You're supposed to do MATH??
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Old 07-07-11, 08:46 PM   #9
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Or you can just count on your fingers and toes.
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Old 07-07-11, 08:53 PM   #10
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Or you can just count on your fingers and toes.
That would get me to 22! That's a great average speed.
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Old 07-07-11, 09:00 PM   #11
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Oh, I thought you meant what was our individual average speed. 22 is about my top speed down a wimpy underpass.
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Old 07-08-11, 05:45 AM   #12
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Is this a SAT test? Do trains still leave Denver @ .....
Looks like most folks are going to make it into college, but only into colleges west of Denver.
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Old 07-08-11, 05:48 AM   #13
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Or you can just count on your fingers and toes.
Or I would just look at my Garmin and let it do the math for me

Math was never my favorite subject........
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Old 07-08-11, 06:50 AM   #14
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I find that I go much faster and farther when I ride a bike that doesn't have a computer and estimate speed and distance.
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Old 07-08-11, 07:50 AM   #15
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Two degrees is enough for me. Math is boring. Tunes rule. There's nothing west of Denver but fruits and nuts.
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Old 07-08-11, 08:15 AM   #16
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Try figuring out a golf handicap index some time.
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Old 07-08-11, 08:21 AM   #17
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hint: (a+b)/(c+d) not equal to (a/c) + (b/d)
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Old 07-08-11, 08:22 AM   #18
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20/1.5
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Old 07-08-11, 09:11 AM   #19
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20/1.5
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Old 07-08-11, 09:56 AM   #20
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20/1.5
There's always someone in the crowd who can't keep a secret
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Old 07-08-11, 10:27 AM   #21
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There's always someone in the crowd who can't keep a secret
Probably that same one in every class in school who would raise his hand after every question saying "me, me, call on me..."
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Old 07-08-11, 10:43 AM   #22
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I find that I go much faster and farther when I ride a bike that doesn't have a computer and estimate speed and distance.
Agreed. Computers have a terrible effect on performance. Must be all that magnetic drag.
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Old 07-08-11, 10:49 AM   #23
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My average speed on the street is pretty slow, much faster on the San Gabriel River Trail, but I'm not sure many have the luxury of an almost flat, nearly empty smooth trail with (almost) no stops on which to measure their speed...
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Old 07-08-11, 12:29 PM   #24
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You probably want the 4th grade arithmetic answer but I like to wander a bit. Okay, maybe more than a bit. Going ten miles can easily involve an extra ten miles of "Wonder what might be down that road/street/trail" and given that I never ride on a plane surface we'd have to get into various schemes for describing the topology of non-linear surfaces.
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Old 07-08-11, 06:27 PM   #25
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Originally Posted by DnvrFox View Post
Just for FUN, please. Most of you have done this before, others may find it new and perhaps surprising. Anyway, it's time to revisit calculating average speed.

OK - if one goes 10 miles at 20 miles per hour and 10 miles at 10 miles per hour, what is the average speed?

Please check your answer above.

Again, just for FUN
Vavg is equal to total distance divided by total time, assuming all time was spent riding as stated. Total distance is 10 +10 = 20. Total time duration is 10/20 +10/10, or 3/2 hours. Dividing 3/2 into 10, we get a long division problem of 40/3. The answer to that is 13.3 mph, rounded to one decimal place.
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