Question 1041334
RT=J  rule for work rates.  J is for quantity of jobs, here being 1.


Original plan was  {{{15*t=1}}} to expect {{{1/15}}} days.
NO!
Change that to j, unknown number of hectares.


{{{15t=j}}}
{{{t=j/15}}}, time in days to do j hectares.


{{{15*4+(15*(4/3))*x=j}}}, ONE unit for j was performed.
x was number of days at the higher rate.
{{{4+x=j/15-1}}}-----time taken total was one day less than expected.  Solve this for j, and substitute.


I did not finish this, but said how you can.