Question 1058797
Some values you know (given or calculated) and some things you do not know.
<pre>
              RATE         TIME         DISTANCE
BIKE          2*8r         1.75
RUN           8r
SWIM           r            1
Total                                     55
</pre>

Give a variable to unknown running speed and fill in everything.

<pre>
              RATE         TIME         DISTANCE
BIKE          16r         1.75           28r        
RUN           8r            t            8rt
SWIM           r            1             r
Total                                     55
</pre>

Notice some trouble?  WHY?  I missed seeing the "ran for one hour".  the variable t is KNOWN!   This will be corrected here:


<pre>
              RATE         TIME         DISTANCE
BIKE          16r         1.75           28r        
RUN           8r            1            8r
SWIM           r            1             r
Total                                     55
</pre>


Everything is filled and looks good.  There is a sum of distances in just the one single variable, r.


{{{highlight(28r+8r+r=55)}}}
Solve for r, and this is the swimming speed.