Answer: the speed of the current is 0.6 mph
Step-by-step explanation:
Let x represent the speed of the current.
James is kayaking. He can row 3 mph in still water. If he can travel 6 miles downstream. Assuming he went with the current, it means that his total speed while travelling downstream is (3 + x)
Time = distance/speed
Time taken to travel downstream is
6/(3 + x)
In the same amount of time, he can travel 4 miles upstream. Assuming he went against the current, it means that his total speed while travelling downstream is (3 - x). Time taken to travel upstream is
4/(3 - x)
Since the time is the same, then
6/(3 + x) = 4/(3 - x)
Cross multiplying, it becomes
6(3 - x) = 4(3 + x)
18 - 6x = 12 + 4x
4x + 6x = 18 - 12
10x = 6
x = 6/10
x = 0.6 mph
