Mary leaves San Francisco and travels toward Los Angeles at

Mary 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 Mary to meet Phil?

Solution

Let t = Mary\'s time on the road
:
(t-1) = Phil\'s time on the road; (He left 1 hr later)
:
When they meet, they will have traveled a total 380 miles
:
Write a distance equation; distance = speed * time
:
Mary\'s distance + Phil\'s distance = 380
50t + 60(t-1) = 380
:
50t + 60t - 60 = 380
:
110t = 360 + 60
:
t = 440/110
:
t = 4 hrs is Mary\'s time on the road