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A boat moves at a rate of 13 mph in still water. If the rivers current flows at a rate of 4 mph, how long does it take the boat to travel 20 miles upstream?

It takes ___ hours.


Sagot :

Answer:

  • 2 2/9 hours

Step-by-step explanation:

Speed upstream is reduced:

  • 13 - 4 = 9 mph

Time to travel 20 miles:

  • 20/9 = 2 2/9 hours

Answer:

20/9 hours

Step-by-step explanation:

Note: I'm assuming 'upstream' means against the current.

If the boat flows against the current, it's speed is 13 - 4 = 9 mph.

[tex]\frac{20m}{9mph} =\frac{20}{9} hours[/tex]

That means our answer is 20/9 hours.

If it is travelling with the current, its speed is 13 + 4 = 17 mph.

Therefore, 20/17 would be our answer if that were the case