SOLUTION: The speed of a stream is 5mph. A boat travels 8 miles upstream in the same time it takes to travel 18 miles downstream. What is the speed of the boat in still water?

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Question 909135: The speed of a stream is 5mph. A boat travels 8 miles upstream in the same time it takes to travel 18 miles downstream. What is the speed of the boat in still water?
Answer by clearblueskai(22) About Me  (Show Source):
You can put this solution on YOUR website!
x - speed of the boat in still water
x-5 - speed of the boat upstream
x+5 - speed of the boat downstream
speed=%28distance%29%2F%28time%29
Downstream:x%2B5=18%2Ft
t=18%2F%28x%2B5%29
since time is the same,
Upstream:
x-5=8%2F%2818%2F%28x%2B5%29%29
x=13