Day 1: 70(.20)=<<70*.20=14>>14 miles

70-14=<<70-14=56>>56 miles remaining

Day 2:56/2=<<56/2=28>>28 miles

56-28=<<56-28=28>>28 miles remaining

# Answer

28
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Bob, a marathon runner, is preparing for a race.  He runs a total of 70 miles in the 3 days leading up to the race. On day one he runs 20 percent of the total miles and on day 2 he runs 50 percent of the remaining miles.  How many miles does he run on day three to complete the 70 miles?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
28
Bob, a marathon runner, is preparing for a race.  He runs a total of 70 miles in the 3 days leading up to the race. On day one he runs 20 percent of the total miles and on day 2 he runs 50 percent of the remaining miles.  How many miles does he run on day three to complete the 70 miles?
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