When a = 50:
2(50) + 20 = 100 + 20 = 120
When a = 150:
2(150) + 20 = 300 + 20 = 320
When a = 250:
2(250) + 20 = 500 + 20 = 520
When a = 50:
2(50) + 20 = 100 + 20 = 120
When a = 150:
2(150) + 20 = 300 + 20 = 320
When a = 250:
2(250) + 20 = 500 + 20 = 520