Answer:
I would hire 4 workers
Explanation:
Marginal cost is $95 for each case
Now we cale to solve for marginal revenue
1st employee:
(21 - 0) x 6 = 126
2nd employee
(40 - 21) x 6 = 114
3rd employee
(59 - 40) x 6 = 114
4th employee
(75 - 59) x 6 = $96
5th employee
(85 - 75) x 6 = 60
As after the fourth employee the amount of additional duplicated is lower than the employee wages it will not hire more.