Question 55158
Ching leaves San Francisco and travels toward Los Angeles at 50 mi/h.  An hour later, Phil leaves Los Angeles and travels toward San Francisco at 60 mi/h.  If the two cities are 380 miles apart, how many hours will it take for Ching to meet Phil?
The formula for distance is {{{highlight(d=rt)}}}, where d=distance, r=rate (or speed) and t=time
Ching's rate=50 mi/h
Ching's time=t
Ching's distance=50t
Phil's rate=60 mi/h
Phil's time=t-1  (Because he left an hour later, he drove an hour less.)
Phil's distance=60(t-1)
The total distance traveled=380 mi 
Problem to solve for t:
50t+60(t-1)=380
50t+60t-60=380
(50+60)t-60=380
110t-60=380
110t-60+60=380+60
110t=440
110t/110=440/110
t=4
Ching will have to travel t=4 hrs.
(they didn't ask, but Phil would travelt-1=4-1=3hrs.)
Happy Calculating!!!