SOLUTION: Need equation:Jane leaves school and walks home at a rate of 4 mi/hr. 15 minutes later, Bill finds a book that Jane forgot and runs at a rate of 8 mi/hr. How many minutes will it t
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Question 1004968: Need equation:Jane leaves school and walks home at a rate of 4 mi/hr. 15 minutes later, Bill finds a book that Jane forgot and runs at a rate of 8 mi/hr. How many minutes will it take Bill to catch up with Jane?
I know she has walked 1 mile in 15 minutes (1/4 hour @ 4 mi/hr is 1 mile). At his pace, it will take 1/2 that time to walk the same distance. But do I consider that she is walking away from him at same time? Don't know how to put in equation format. Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website! Jane's head start in miles: mi
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Now imagoine that you start a stopwatch
when Bill leaves.
Let = time in hours on stopwatch
when Bill catches Jane
Let = distance in miles Bill travels
until he catches up with Jane
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Bills equation:
(1)
Jane's equation:
(2)
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Substitute (1) into (2)
(2)
(2)
(2)
It will take Bill 15 min to catch Jane
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check:
(1)
(1)
(1)
and
(2)
(2)
(2)
(2)
OK