Expert: Will Dwinnell - 8/29/2004

Question
Hello:

I want to thank you for your prompt reply.

It seems unmathematical to simply invert miles/hour to hours/mile. I thought that there may be a calculation that can be used to prove that (1/2 mile/hour) equals (2 hours/mile). Flipping this ratio or rate seems to be a shortcut method. Something like miles/hours divided by [(miles/hour)/(hours/mile)] might work, but I'm not sure. This might result in miles/hour X [(hours/mile)/(miles/hour)] = hours/mile.
Does this calculation make sense?

I thank you for your follow-up reply.
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Followup To
Question -
Hello:

How does 1/2 of a mile per hour (1/2 mile/hour) convert to hours per mile? I do not want to simply invert the fraction to 2 hours per mile (2 hours/mile).
Is there a calculation that can be used?

I thank you for your reply.

Answer -
I'm not quite sure what you're asking- please feel free to write again.  A rate of 1/2 mile per hour  is  equivalent to 2 hours per mile.  The calculation I would use is to invert the mph to get hpm.  Is there some reason you don't want to do that?

-Will Dwinnell
http://will.dwinnell.com  

Answer
I hate to disappoint, but I think it is as simple as inverting one figure to get the other.  In any given circumstance, A miles are travelled in B hours' time.  Calculating miles per hour involves dividing oen way, A/B, while calculating hours per miles involves dividing the other way, B/A.  The obvious algebra means that X mph = 1/X hpm.

-Will Dwinnell
http://will.dwinnell.com