He volunteers 2*12=<<2*12=24>>24 times a year

So he volunteers for 24*3=<<24*3=72>>72 hours

# Answer

72
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
John volunteers at a shelter twice a month for 3 hours at a time.  How many hours does he volunteer per year?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
72
John volunteers at a shelter twice a month for 3 hours at a time.  How many hours does he volunteer per year?
train