Three workers can do a job in 28 hours. how many more workers are needed to do this job in 12 hours?

4 additional workers for 7 total workers.
if it takes 3 workers 28 hours to do work there are 84 total hours of work (3*28=84) to find how many workers it will take to get the work done in 12 hours divide 84 by 12. 84/12= 7 total workers. 7-3= 4 additional workers needed.

128/3reason being 5 and 1/3 = 16/316/3 • 2/3 = 32/31 and 1/3 = 4/3 32/3 • 4/3 this will equal 128/3