SOLUTION: Two dog teams racing the last 77 miles.Team B leaves 13 minutes after Team A.Team A is doing 7 mph.how fast does team B go to pass and get to finish line first.

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Question 725185: Two dog teams racing the last 77 miles.Team B leaves 13 minutes after Team A.Team A is doing 7 mph.how fast does team B go to pass and get to finish line first.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Team B needs to go faster than a speed that will
give them a tie right at the finish line
Team A has a head start of
+7%2A%2813%2F60%29+=+1.51667+
Let +t+ = the time for them both to meet
at the finish line after B leaves
Let +s+ = B's speed in mi/hr
--------------------------
A's equation:
(1) +77+-+1.51667+=+7t+
B's equation:
(2) +77+=+s%2At+
---------------
(1) +7t+=+75.48333+
(1) +t+=+10.78333+
--------------------
(2) +s+=+77%2Ft+
(2) +s+=+77%2F10.78333+
(2) +s+=+7.14065+
Team B needs to go faster than 7.14065 mi/hr
check:
(1) +77+-+1.51667+=+7%2A10.78333+
(1) +75.48333+=+75.48333+
OK
(2) +77+=+s%2At+
(2) +t+=+77%2F+7.14065+
(2) +t+=+10.78333+
OK