The minimum total amount of people is the children plus the adults.
22 + 18 = 40 total
Divide the amount of children by the total amount (and then multiply by 100) to find how much (what percentage) of the crowd is made of children.
22 children/40 total people = 0.55
0.55 * 100 = 55% of the crowd are children
Answer: 55% of the crowd are children
