SOLUTION: A car leaves a town traveling at 40 miles per hour. Two hours later a second car leaves traveling the same route and overtakes the first car in 5 hours. How fast was the second tra
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Question 227082: A car leaves a town traveling at 40 miles per hour. Two hours later a second car leaves traveling the same route and overtakes the first car in 5 hours. How fast was the second traveling? Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Assume I have a stopwatch, and I start it
when the 2nd car leaves
How far has the 1st car gone when I start
the stopwatch? mi
The key to the problem is that, after the
stopwatch starts, both cars will travel
for the same amount of time
Let = distance 2nd car must go to
catch 1st car in mi
Let = speed of 2nd car in mi/hr
For 1st car:
(1)
For 2nd car:
(2)
This is 2 equations and 2 unknowns, so it's solvable
(1) mi
And, substituting,
(2)
The speed of the 2nd car was 56 mi/hr
