A river has a steady speed of 0.500 m/s. A student swims M upstream a distance of 1.00 km and swims back to the Q/C starting point. (a) If the student can swim at a speed of 1.20 m/s in still water, how long does the trip take? (b) How much time is required in still water for the same length swim? (c) Intuitively, why does the swim
take longer when there is a current?
Vse = Vsr - Vre
The Attempt at a Solution
I done this problem by adding the velocity of the swimmer and current vectorialy to get the relative speed if student w.r.t to Earth then when I searced for the solution they had just added the two speed for the upward motion and subtracted them for downward motion. I am really confused i don't know what's going on