Question 1031576
<pre>
             SPEED       TIME         DISTANCE

NORTHWARD     r-20       {{{1/5}}}         {{{(r-20)/5}}}

EASTWARD       r         {{{1/5}}}         {{{r/5}}}

SEPARATION                             20
</pre>
The 12 minutes travel time is {{{(1/5)hour}}}.


The north and east distances form the legs of a right triangle, making distance relationship
conforming to Pythagorean Theorem Formula.


{{{highlight(((r-20)/5)^2+(r/5)^2=20^2)}}}
Solve this for r.