<PRE><B>Question 1131101</B>
10 mph MORE or LESS?  Which is missing?

&lt;pre&gt;
If first part of trip 10 mph more than second part, then:

              SPEED        TIME          DISTANCE

first part      r+10       120/(r+10)      120

last part        r         100/r           100

TOTAL                        4
&lt;/pre&gt;
{{{120/(r+10)+100/r=4}}}



If instead the description is  that the 120 miles was done at 10 mph LESS than the last 100, then this equation:
{{{120/(r-10)+100/r=4}}}</PRE>