Answer: There were 7 children
Step-by-step explanation:
Let's use <em>x </em>to represent the children and <em>y </em>to represent the adults.
We know they combine to make a group of 25 people so x+y=25
We also know that they paid $201 and that there is $3 per child and $10 for adults so 3x+10y=201
I will solve by substitution.
Solve for y in the first equation
![x+y=25\\x-x+y=25-x\\y=25-x](https://tex.z-dn.net/?f=x%2By%3D25%5C%5Cx-x%2By%3D25-x%5C%5Cy%3D25-x)
Sub in our value for y into the other equation and solve for x
![3x+10y=201\\3x+10(25-x)=201](https://tex.z-dn.net/?f=3x%2B10y%3D201%5C%5C3x%2B10%2825-x%29%3D201)
Step 1) Simplify
![3x+250-10x=201\\-7x+250=201](https://tex.z-dn.net/?f=3x%2B250-10x%3D201%5C%5C-7x%2B250%3D201)
Step 2) Subtract 250 from both sides
![-7x+250-250=201-250\\-7x=-49](https://tex.z-dn.net/?f=-7x%2B250-250%3D201-250%5C%5C-7x%3D-49)
Step 3) Divide both sides by -7
![\frac{-7x}{-7} =\frac{-49}{-7}\\x=7](https://tex.z-dn.net/?f=%5Cfrac%7B-7x%7D%7B-7%7D%20%3D%5Cfrac%7B-49%7D%7B-7%7D%5C%5Cx%3D7)