Answer:
Vs/c = 20 [m/s]
Explanation:
This is a problem of relative velocities, as velocity is a vector we can use addition or subtraction of vectors for the solution.
We are asked for the velocity of the sailboat with respect to an observer located in the canoe.
[tex]V_{s/c}=V_{sailboat}-V_{canoe}\\V_{s/c}=15-(-5)\\V_{s/c}=20[m/s][/tex]
Why is the speed of the canoe negative?, it is negative because the canoe moves in the opposite direction to the sailboat.