Peter has to walk a remaining 2.5 total miles - 1 mile completed = <<2.5-1=1.5>>1.5 miles remaining

It will take him another 20 minutes * 1.5 miles remaining = <<20*1.5=30>>30 minutes to get to the grocery store

# Answer

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<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Peter has to walk 2.5 miles to get to the grocery store. If it takes him 20 minutes to walk one mile and he has walked 1 mile already, how many more minutes does he have to walk to reach it?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
30
Peter has to walk 2.5 miles to get to the grocery store. If it takes him 20 minutes to walk one mile and he has walked 1 mile already, how many more minutes does he have to walk to reach it?
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