Problema Solution
canoeing. Kahla paddled for 4 hours with a 6km/h current to reach a campsite. The return trip against the same current too 10 hours. Find the speed of Kahla's canoe in still water.
Answer provided by our tutors
Let k = Kahla's speed in still water
Her speed paddling with the current is her speed in still water plus the speed of the current = k + 6km/hr
Her speed paddling against the current is her speed in still water minus the speed of the current = k - 6km/hr
Going to the campsite took 4 hr and her speed was k + 6km/hr. Plug that into d = rt
d = (k+6)4 = 4k + 24
Returning from the campsite took 10 hr and her speed was k - 6km/hr. Again plug those into d = rt
d = (k - 6)10 = 10k - 60
The 2 distances are the same so
4k + 24 = 10k - 60
4k - 10k = -60 - 24
-6k = -84
k = 14
Kahla's speed in still water is 14km/hr