If there are 600 people at the fair this year, the number going to the fair next year is 2*600 = <<2*600=1200>>1200.
The number of people at the fair this year and the ones going next year totals 1200+600 = <<1200+600=1800>>1800
The number of people who went to that fair last year was 200 less than those going next year, meaning there were 1200-200 = 1000 people at the fair last year.
In the three years, the number of people at the fair will be 1800 of this and next year + 1000 of last year = <<1800+1000=2800>>2800
#### 2800