Question 933374
RT=D, T=D/R.



__________________rate__________time__________distance
UP________________16____________(___)__________d/3
LEV_______________24___________(____)__________d/3
DWN_______________(___)________(____)__________d/3
Total__________________________(____)__________d




__________________rate__________time__________distance
UP________________16____________(d/(3*16))__________d/3
LEV_______________24___________(d/(3*24))__________d/3
DWN_______________(r)________(d/(3r))__________d/3
Total__________________________(____)__________d



The total time would be {{{d(1/(3*16)+1/(3*24)+1/(3r))}}}; which needs simplification before comfortably using this expression.  The AVERAGE speed would be {{{d/(d(1/(3*16)+1/(3*24)+1/(3r)))}}}
{{{1/(1/(3*16)+1/(3*24)+1/(3r))=24}}};
LCD is 3*2*2*2*2, 3*2*2*2*3, 3*r,------{{{highlight_green(3*3*2*2*2*2*r)}}};
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Another way to continue is use reciprocals of both members.
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{{{1/(3*16)+1/(3*24)+1/(3r)=1/24}}}
Now multiply both members by LCD.
{{{(3^2*2^4*r)(1/(3*16)+1/(3*24)+1/(3r))=144r/24}}}
{{{3r+2r+48=6r}}}
{{{5r+48=6r}}}
{{{highlight(r=48)}}}