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A boat traveled 54 km with the stream and 42 km against the stream spending a total of as much time as it would spend while travelling 96 km in a lake. Find the speed of boat while it is travelling in the lake, if the current of the river is 3 km/hour.


Hii! If someone can like show how they got this I would really appreciate it! Thank you so much. I kinda need it quick

Respuesta :

mhanifa

Answer:

  • 24 km/h

Step-by-step explanation:

  • The speed of the boat  in the lake = x
  • The speed of the current = 3 km/h

Required equation:

  • 54 / (x + 3) + 42 / (x - 3) = 96/x
  • 9x(x - 3) + 7x(x + 3) = 16(x + 3)(x - 3)
  • 9x² - 27x + 7x² + 21x = 16x² - 144
  • 6x = 144
  • x = 144/6
  • x = 24 km/h

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