39
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
The sequence $2, 7, 12, a, b, 27$ is arithmetic. What is the value of $a + b$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
39
The sequence $2, 7, 12, a, b, 27$ is arithmetic. What is the value of $a + b$?
train