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?
Each additional worker hired reduces the time by 4 days
To reduce the job by 20 days
4 x = 20 where x is the number of additional workers needed
x =20 / 4 = 5 additional workers should be hired
+830 
