Question 1132341
<pre>
                   SPEED       TIME       DISTANCE

FIRSTPART           r          25/r        25

SECONDPART         r+15        65/(r+15)   65

TOTAL                           1.5        90
</pre>


{{{25/r+65/(r+15)=1.5}}}
Solve for r.


Simplification steps should lead to {{{cross(r^2-45r-150=0)}}}.







-
(Mistake made in steps done off-site  --
Equation should simplify to {{{r^2-45r-250=0}}}).