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?
x=additonal workers that need to be hired.
To complete the job 20 days earlier: 4x
x=20/4=5
5 additional workers should be hired.
Given
J/5 = D or 5D = J
and
J/ (5+1) = D - 4 Sub in '5D' for 'J'
5D / 6 = D- 4
shows D = 24 days
24 days x 5 workers = 120 Worker Days for the job
if you have 6 workers it will take 120/ 6 = 20 Days (which is FOUR days less...Check !)
Now ....how many workers to get the job done in only FOUR days ( which is 20 days earlier)
120 Worker Days / 4 Days = 30 workers needed or hire 25 ADDITIOANL workers to add to the original five