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

The answer is B. 25 adults; 15 children.

If I were to answer this, I will use 2 equation. First, let x be the number of adults and y be the number of children. Where : x+y=40 and 22x+18y=820. Let us use the substitution method. We'll use the first equation because it's more simple. If x+y=40, then x=40-y. Then, let's substitute the value of x in the equation number 2. If 22x+18y=820, then, 22 (40-y) + 18y=820. Simplifying it, we'll get the value of y which is 15. Then, let's substitute the value of y to the first equation to get the value of x which is 25. Therefore, if x = 25 and y = 15, there should be 25 adults and 15 children in the group.