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Setting Up Proportions and Unit Conversions


Date: 7/25/96 at 20:36:31
From: Anonymous
Subject: Setting Up Proportions and Unit Conversions

If you can run 100 meters in 10 seconds, how long, in days, hours, and 
minutes, does it take you to run 12,800,000 meters?


Date: 7/26/96 at 0:38:13
From: Doctor Paul
Subject: Re: Setting Up Proportions and Unit Conversions

Let's set up a proportion:

100 meters      12,800,00 meters
---------- =    ----------------
10 seconds         x seconds

x = 1,280,000 seconds.  Now we have to convert that to days:

                           1 hour           1 day
1,280,000 seconds    x   ------------  x   --------
                         3600 seconds      24 hours

so that's equal to 14.814 days.  Let's now convert .814 days into 
hours:

.814 day       1 day
--------  =   -------
 x hours      24 hours


so .814 day = 19.536 hours

So right now we have 14 days, 19.536 hours.  We need to convert .536 
hours into minutes..

.536 hours       1 hour
---------- =     -------
 x minutes     60 minutes

x = 32.16 minutes.

Since your answer doesn't want seconds we round that to 32 minutes.

The answer is:
14 days, 19 hours, 32 minutes.

-Doctor Paul,  The Math Forum
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Associated Topics:
Middle School Ratio and Proportion
Middle School Word Problems

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