The speed of the current in a creek is 3 mph. A person can kayak 5 mi upstream in the same time that it takes him to kayak 11 mi downstream. What is the speed of the​ person's kayak in still​ water?

Answer 1

11/(3+k) = 5/(k-3) speed/distance = time, d=st, t=d/s

multiply by (k+3)(k-3)

11(k-3) = 5(k+3)

5k+15 = 11k-33

6k = 48

k = 8 mph in still water

time = 11/(3+8) = 5(8-5) = 11/11 = 5/5 = 1 hour

(8-3)=5 mph x 1 hour = 5 miles upstream

8+3 =11 mph x 1 hour = 11 miles down stream