SOLUTION: A boat takes 1 hour to travel 12 miles down river (with the current). Against the same current, it takes 1.25 hours to return up river. If x is the speed of the boat, and y is the
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-> SOLUTION: A boat takes 1 hour to travel 12 miles down river (with the current). Against the same current, it takes 1.25 hours to return up river. If x is the speed of the boat, and y is the
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Question 1113363: A boat takes 1 hour to travel 12 miles down river (with the current). Against the same current, it takes 1.25 hours to return up river. If x is the speed of the boat, and y is the speed of the current, find the speed of the boat and the speed of the river Answer by ikleyn(52803) (Show Source):
The "speed equation traveling downstream" is
= x + y (12 miles divided by 1 hour = the speed traveling downstream = x + y)
The "speed equation traveling upstream" is
= x - y (12 miles divided by 1.25 hour = the speed traveling upstream = x - y)
Rewrite it as the system
x + y = 12 (1)
x - y = 9.6 (2)
Add equations (1) and (2). You will get
2x = 12 + 9.6 = 21.6 ====> x = = 10.8.
Then from (1), y = 12 - 10.8 = 1.2.
Answer. x = 10.8 mph; y = 1.2 mph.
Solved.
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It is a typical and standard Upstream and Downstream round trip word problem.
