Question 985285
The time for all four sides was {{{d/4+d/5+d/10+d/20}}}.  d is the length of each side.


Average speed, {{{4d/(d(1/4+1/5+1/10+1/20))}}}


{{{4/(1/4+1/5+1/10+1/20)}}}


{{{(20/20)(4/(1/4+1/5+1/10+1/20))}}}


{{{80/(5+4+2+1)}}}


{{{80/12}}}


{{{20/3}}}


{{{highlight(6&2/3)}}}