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?
Let the number of days needed for 5 workers to finish the job ==D
5 / 6 ==[D - 8] / D, solve for D
D==48 days - for 5 workers to finish the job.
5 * 48 ==240 - worker-days required
W==additional workers needed
240 / [5 + W] ==48 - 28, solve for W
W==7 - additional workers will be needed
5 + 7 ==12 - total work-force needed
