Answer:
a + b + c = 8 ⇒ answer E
Step-by-step explanation:
∵ 3b is a number with unit digit 2
∴ Let 3b = 12 ⇒ b = 4
∵ a < b ⇒ 3a + 1 = 4 ⇒ 3a = 3
∴ a = 1
∴ abb = 144
∴ abb + abb + abb = 144 + 144 + 144 = 432
∵ abb + abb + abb = bc2
∴ c = 3
∴ a + b + c = 1 + 4 + 3 = 8
