Dinosaur Park tickets cost 90 yuan to buy 100 people, 70 yuan. There are 3 to 4 people in Team A and Team B, so it costs more to buy separately than to buy together 1800 yuan. ...
Solution: If two teams have X people, then team A has 3/7x people and team B has 4/7x people.
3/7x×90+4/7x×70-70x= 1800
x=2 10
You can think of the number of people in team B as 100, and you will find that it is not an integer, so it can only be more than 100.