Five workers have been hired to complete a job. If one additional worker is hired, they could complete the job $4$ days earlier. If the job needs to be completed $20$ days earlier, how many additional workers should be hired?
ratio of people: 5/6
ratio of work time: 6/5 = x/x-4
x = 24so 4 days - 25 more people
5D = the man hours for the first job where D is the number of days
6(D - 4) = the man hrs if one additional person is hired
Since the man hours are equal
5D = 6D - 24
D = 24
5D = 5 (24) = 120 man hours
So ....let N be the number of workers needed to complete the job 20 days earlier
N ( 24 - 20) = 120
4N = 120
N = 30
30 - 5 = 25 additional workers should be hired