<PRE><B>Question 1025389</B>
Travel periods are 18 hours each period.


Let u be the conversion factor from kilometers to miles, as {{{u(km/mile)}}}.


{{{RT=D}}}
{{{T=D/R}}}


{{{20000*km*(1/45)(hour/miles)*(1/u)(mile/km)}}}, but this is total time IN HOURS.  Now you have  1 day = 18 hours as a conversion ratio also.


{{{(20000/(45u))(1/18)}}}, the number of days if travel period is 18 hours per day.</PRE>