Question 1049669
Look at time quantities first, and no adjustments for time points later needed.  Second train begins travel five hours after the New York departure train.  The overtake time is  9-2=7 hours for the New York first departure train, and 9-7=2 hours for the second train.

<pre>
Which Depart Time    SPEED         TIME        DISTANCE
2PM TRAIN              r            7            d
7PM TRAIN             r+150         2            d
</pre>


Basic constant travel rate rule is RT=D.


{{{system((r)(7)=d,(r+150)(2)=d)}}}


{{{highlight(7r=2(r+150))}}}