River Current Speed: 2m/s or 4m/s?

AI Thread Summary
The discussion centers on determining the current speed of a river based on Shareen's motorboat speeds upstream and downstream. The calculations show that the current speed is 2m/s, derived from the equations x + b = 12m/s and b - x = 8m/s. Some participants debate whether the current could be 4m/s, but the algebra consistently supports 2m/s as the correct answer. The inconsistency in boat speed when assuming a 4m/s current further reinforces the conclusion. Ultimately, the correct current speed is confirmed to be 2m/s.
Krystan
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Homework Statement



Shareen finds that when she drives her motorboat upstream she can travel with a speed of only 8m/s, while she moves with a speed of 12m/s when she heads downstream. What is the current of the river on which Shareen is traveling?


The Attempt at a Solution



x= current speed
b= boat speed

x+b= 12m/s
b-x= 8m/s
b=x+8
x+x+8= 12
2x= 4
x=2

12m/s-8m/s=4m/s

Our physics class is having a debate on whether the answer is 2m/s or 4m/s and why.
 
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I agree with your first answer, for reasons the algebra suggests. Maybe solve for the boat speed in either case? It will likely be inconsistent at 4m/s.
 

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