Question 981664
Maybe easier to use time only in hours and solve for that first.


14 days at 12 hours per day
14*12
168 hours


{{{system(15r*168=1,21r*h=1)}}}


{{{r=1/(15*168)}}}
substitute in the "h" equation.
{{{h=1/(21*r)}}}
{{{h=(1/21)(168*15)}}}
{{{h=(168*15)/21}}}
{{{highlight(h=120*hours)}}}
-
These hours would then be distrubuted through 10 hours/day, so
{{{highlight(120*hours(1/10)(days/hour)=highlight(12*days))}}}