Question

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

Answer 1

• 24 km/h

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