A group of children and their parents went to an amusement park. There were a total of 40 people in the group. The tickets cost $22 for each adult and $18 for each child. They paid a total of $820 for the tickets. How many adults and how many children are in the group that went to the amusement park? A. 15 adults; 25 children B. 25 adults; 15 children C. 18 adults; 22 children D. 12 adults; 28 children