A train leaves Chicago traveling west at 60 miles per hour. An hour later, another train leaves Chicago traveling east at 80 miles per hour. When are the two trains the same distance from Chicago?
One train gets a 60 mile head start...its distance from Chicago will be given by
60 + 60 x miles where x = hours after 2nd train starts
2nd train distance = 80 x when are these two distances equal?
60 + 60x = 80x
x = 3 hours after sencond train starts 4 hours after first train started
Another way:
train 1 has 60 mile head start train 2 travels 20 m/hr faster to close that 60 mile head start will require 60 m / 20m/hr = 3 hours