Question 964326
{{{80mi/280mi=x/(x+100)}}}
{{{80x+8000=280x}}}
{{{8000=200x}}}
{{{40=x}}} 
ANSWER 1: The rate of the train is 40 mi/hr.
40mph+100mph=140mph
ANSWER 2: The rate of the plane was 140 mi/hr.