Let same number of hours = x, since the salary earned is also the same, then Salary of supervisor A = $25x Salary of supervisor B = $20(30)+$30(x-30) Equating 25x=600+30(x-30) 30x-25x=900-600 5x=300 x=60 hours Check: Salary of supervisor A = 25*60=1500 Salary of supervisor B = 20*30+30*(60-30)=600+900=1500, ok.