Question 1059416
HOW MANY square feet?  Not in the description, so if assume the 18 workers in 8 hours will paint some p square feet of wall area, then you can just use this variable.  


BASIC RULE:  J/T=R, or jobs per time is a constant, R.  J for amount of job, T  for amount of time.  Easily rewrite as RT=J.
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If some n workers are acting together, then rate is nR.


Let r be rate of one worker.
Let x be the amount of area for the 25 workers to do in 6 hours.
Assume that p is KNOWN, but as asked, x is UNKNOWN.



{{{system(18r*8=p,25r*6=x)}}}
Solve this system for x.  


First equation gives you {{{r=p/(18*8)}}}; substitute into the second equation.


{{{x=25(p/(18*8))*6}}}


{{{x=(25*6*p)/(18*8)}}}


{{{x=(25p)/(3*8)}}}


{{{highlight(x=25p/24)}}}, square feet of area.  If you want a finished value, you need to be given what is p.  Here, it is still a variable.