Question 1185644
Going,  {{{580/20}}} or 29 meters per minute

Returning, {{{580*meters*(1/20)(minutes/meters)=29}}} minutes



total distance,  {{{2*580=1160}}} meters
total time {{{20+29=49}}} minutes


Average speed, {{{(1160/49)(meters/minute)}}}

23.7 meters per minute