SOLUTION: Two cities A and B are connected by means of highway. A car leaves at 10:00PM and travels at 40mil/hr toward B. Thirty minutes later , another car leaves A and travels toward at co

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Two cities A and B are connected by means of highway. A car leaves at 10:00PM and travels at 40mil/hr toward B. Thirty minutes later , another car leaves A and travels toward at co      Log On


   



Question 1049707: Two cities A and B are connected by means of highway. A car leaves at 10:00PM and travels at 40mil/hr toward B. Thirty minutes later , another car leaves A and travels toward at constant rate of 55mil/hr. At what time the second car overtake the first car?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
The example is a typical one-of-these exercises:

r, 40 miles per hour, slow car
R, 55 miles per hour, fast car
h, 0.5 hour
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Time quantities come from time points in the description and would need to be readjusted to finish the solution.
-
d, unknown distance upon catchup
t, time for fast car to catchup to slow car


               SPEEDS      TIME      DISTANCE

EARLY SLOW       r          t+h        d

LATE FAST        R           t         d


Constant Travel Rates Rule, if travel rate is K, time is T, distance is D, D%2FT=K.

system%28r%28t%2Bh%29=d%2CRt=d%29
Solve the system for t, and if desired, for d.