Question 502209
d = r*t is the basic distance equation.
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M = Martha's distance.
M = 4 * t
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C = Carol's distance
C = 6 * t
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However, their times are different by 2 hr.
If M's time = t, then C's time = t-2.
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When C catches up, the two have gone the same distance.
M = C
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4*t = 6*(t-2)
4t = 6t -12
-2t = -12
t = 6
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So Carol catches up at the 24 mile post.
That would be 4 pm
Carol ran for 4 hours at 6 mph.
Martha walked for 6 hr at 4 mph
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Carol can catch up an earlier by leaving earlier or by running faster.
Leaving earlier is likely easier.
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Done.