Posted by Avery on .
Two cars, 127 miles apart, start moving towards each other at the same time. One is moving 3 times as fast as the other. If they meet 1.5 hrs later, find the average speed of the slower car in miles per hour?

Physics/Math 
Steve,
slower car moves 127/4 miles in 1.5 hrs
(127/4 mi) / 1.5hr = 21.17 mi/hr 
Physics/Math 
Avery,
Sorry, how did you get that? :(

Physics/Math 
Elena,
v1•t+v2•t=s
v1=v, v2=3v,
v•t+3v•t=4•v•t=s
v=s/4•t =127/4•1.5 =21.17 mph 
Physics/Math 
Avery,
Oh! I understand now, thanks so much to both :)