Question

Jesse takes a 3-day kayak trip and travels 72 km south from Everglades City to a camp area in Everglades National Park. The trip to the camp area with a 2-km/hr current takes 9 hr less time than the return trip against the current. Find the speed that Jesse travels in still water.

Answer 1

Answer: The speed that Jesse travels in still water is 6 km/hr.

Step-by-step explanation:

Let the speed that Jesse travels in still water be 'x'.

Distance = 72 km

The trip to the camp area with a 2-km/hr current takes 9 hr less time than the return trip against the current.

Speed of current = 2 km/hr

According to question, we get that

$\dfrac{72}{x-2}-\dfrac{72}{x+2}=9\\\\\dfrac{x+2-(x-2)}{x^2-4}=\dfrac{9}{72}\\\\\dfrac{4}{x^2-4}=\dfrac{1}{8}\\\\32=x^2-4\\\\32+4=x^2\\\\x^2=36\\\\x=\sqrt{36}\\\\x=6$

Hence, the speed that Jesse travels in still water is 6 km/hr.