Question 768261

John walks {{{d=10mil}}}  at an average rate of {{{s=2 mph}}} 

since {{{d=s*t}}}, we have
{{{10mil=2mph*t}}}
{{{10mil/2mph=t}}}
{{{5h=t}}}......John walks for {{{5h}}}

and returns on a bicycle at an average rate of {{{s=10 mph}}}
since distance is same we will have

 {{{10mil=10mph*t}}}
{{{10mil/10mph=t}}}
{{{1h=t}}}
 
 the entire trip takes him {{{5h+1h=6h}}}

so, the answer is: D) {{{6}}} hours