Answer:
If Karen can laminate 40 posters in 60 minutes, we can calculate her rate as follows:
40 posters / 60 minutes = 2/3 posters per minute.
Now, to find out how many posters Karen can laminate in 4 1/2 hours (which is 270 minutes), we can multiply her rate by the total time:
(2/3 posters per minute) * 270 minutes = 180 posters.
Karen can be expected to laminate around 180 posters in 4 1/2 hours with no work breaks.