If the population is halving then at the end of the third year, the population must have been 60 people in the fourth year * 2 = <<60*2=120>>120 people.

In the second year, the population was 120 people in the third year * 2 = <<120*2=240>>240 people.

And in the first year, the population was 240 people in the third year * 2 = <<240*2=480>>480 people.

Additional people moved out in the first year, so accounting for these shows the population was 480 people + 400 people who moved out = <<480+400=880>>880 people.

Then removing the new people shows there were originally 880 people – 100 new people = <<880-100=780>>780 people.

# Answer

780
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
After 100 new people move into a town, 400 of the original population move out. Every year afterward, the town’s population is halved. After 4 years, the population is 60 people. Before the new people moved in, how many people lived in the town?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
780
After 100 new people move into a town, 400 of the original population move out. Every year afterward, the town’s population is halved. After 4 years, the population is 60 people. Before the new people moved in, how many people lived in the town?
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