Answer:
21 kids have to go on the trip to make the museum a better deal
Explanation:
Zoo: y=10x+100
Museum: y=5x+200
10x+100=5x+200
5x=100
x=20
When 20 kids go on trip the costs will be the same. Therefore, once 21 kids go the museum will be cheaper then the zoo as it is increasing at a rate of 5 dollars