.
1 - One-line solution, Physics style
The distance under the question is 
= 
= 3.5 miles.
2 - One-line solution, Physics style with more explanations
The distance under the question is = = 3.5 miles.
Explanations.
70-60 = 10 mph in the denominator is the relative speed of the cars, i.e. the rate of decreasing the distance between them.
is the time for the second car to catch the car 1.
Thus is "how many miles will it take car 2 to catch car 1".
3 - Algebra style solution using equation
The equation is
70*t = 60*t + 0.5,
which says that the distance to catch for the car 2 is 70*t miles and is 0.5 miles longer than 60*t, which is the distance to travel for the car 1.
From the equation,
t =
is the catching time for the car 2.
Hence, is the distance to catch for the car 2, exactly as it was explained in Solutions 1 and 2.
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For the introductory lessons on Travel and Distance see the lessons
- Travel and Distance problems
- Travel and Distance problems for two bodies moving in opposite directions
- Travel and Distance problems for two bodies moving in the same direction (catching up)
in this site.
