Question 26165
The fly flies untill the trains meet.  So you have to figure out 
how long it took till the trains met.
Data for Wash. to Bos. train:
distance is "x"; rate is 60mph; time is distance/time = x/60
Data for Bos. to Wash. train:
distance is "440-x"; rate is 50mph; time is distance/time = (440-x)/50
EQUATION:
The times must be equal:
x/60 = (440-x)/50
Multiply by 10 to get:
x/6 = (440-x)/5
5x=6(440-x)
5x=2640-6x
11x=2640
x=240 miles (distance the Wash. to Bost. train traveled at 60mph)
240/60=4hr  (time the Wash. to Bost. train took to meet the other train)
The fly flew for four hours at 80mph, so it flew 4(80)=320miles.

Cheers,
Stan H.

The trai