Answer:
There were 30 children and 10 adults.
Step-by-step explanation:
Since they sold tickets to adults and childrens, the sum of those tickets must be equal to the total tickets that were sold, so we can mount our first equation as shown below:
adult + children = 40
Each adult ticket costs $9 and each children costs $5 and the total recieved was $240, therefore:
9*adult + 5*children = 240
We can mount the following equation system:
adult + children = 40
9*adult + 5*children = 240
We will multiply the first equation by -5 and sum both equations:
-5*adult -5*children = -200
9*adult + 5*children = 240
4*adult = 40
adult = 40 / 4
adult = 10
adult + children = 40
children = 40 - adult = 40 - 10 = 30
There were 30 children and 10 adults.
