Question 977226
Yes you are right but you could set it out like this:
(80x+5000)/x<=100 so that we have 80x+5000<=100x, if we collect like terms, this inequality turns to: 80x-100x<=-5000 so -20x<=-5000 and x>=250. 
What you left out is the inequality sign, everything else is fine.
Hope this helps!