Given:
Price of the shirts : $5
hourly wage: $12
cost of material for each shirt: $1
Current Level
20 workers: 20 12 = 240
70 shirts per hour: 70 1 = 70
70 shirts sold at 5 = 70 5 = 350
Profit = Sales - Cost
P = 350 - 240 - 70
P = 350 - 310
P = 40
21 workers : 72 shirts
P = (725) - (2112) - (721)
P = 360 - 252 - 72
P = 360 - 324
P = 36
15 workers : 60 shirts
P = (605) - (1512) - (601)
P = 300 - 180 - 60
P = 300 - 240
P = 60
16 workers : 63 shirts
P = (635) - (1612) - (631)
P = 315 - 192 - 63
P = 315 - 255
P = 60