<PRE><B>Question 1078852</B>
Work-rates  nR*T=W  for work W, n workers, R rate for one worker, time T.


If keep the time units as HOURS, then the fifty workers for twenty DAYS were as

{{{50r*8*20=1200}}}


{{{r=(3/20)(METERS/HOURS)}}}



Now the contractor wants to be sure to finish in 10 days at 10 hours per day, and wants to know many more workers to hire.  Length needing to be done is {{{3000-1200=1800}}} meters.


{{{(n+50)(3/20)(10*10)=1800}}}


n=70
Need to hire 70 more workers</PRE>