math
posted by Bob .
drove from rich to boston at avg speed of 50 mph,if it took 5 hrs to drive from rich to phila at an avg speed of 70 mph and if the whole trip took 13 hrs how far is it from phila to boston?

Answered earlier today:
http://www.jiskha.com/display.cgi?id=1282735117 
"Rich?" Is that supposed to be Richmond VA?
Rich to Phila distance = 70x5 = 350 miles
Boston to Phila distance = X
(X + 350)/13 = 70 mph
Solve for X