Five workers have been hired to complete a job. If one additional worker is hired, they could complete the job $8$ days earlier. If the job needs to completed $28$ days earlier, how many additional workers should be hired?
so, basically, say x is the amount of days 1 person can do the task in. then x/5-x/6=8, meaning x=240, and 5 workers take 48 days, so if you want to take 20 days, you have to have 12 workers. 12-5 = 7, so you need 7 extra workers!