Given:
a.) The admission fee at a small fair is $2.50 for children and $4.00 for adults.
b.) On a certain day, 2400 people enter the fair and $7140 is collected.
Let,
x = total number of children
y = total number of adults
Let's generate two equations based on the given scenario:
EQUATION 1: Total number of children and adults entered the fair.
![\text{ x + y = }2400](https://img.qammunity.org/2023/formulas/mathematics/high-school/39pw4wjuork8sc5xcn78jngiw19f7tey6s.png)
EQUATION 2: Total money collected from the admission.
![\text{ 2.5x + 4y = }$7140$](https://img.qammunity.org/2023/formulas/mathematics/high-school/8jzpqg0qqzgrdz3fxyowrx1pq6dkva4nut.png)
We will be using the substitution method. We get,
![\text{ x + y = }2400](https://img.qammunity.org/2023/formulas/mathematics/high-school/39pw4wjuork8sc5xcn78jngiw19f7tey6s.png)
![\text{ y = }2400\text{ - x}](https://img.qammunity.org/2023/formulas/mathematics/high-school/gg2cggixc6s4eqt653setbh6uh7qibngo9.png)
Substitute to Equation 2:
![\text{ 2.5x + 4y = }$7140$](https://img.qammunity.org/2023/formulas/mathematics/high-school/8jzpqg0qqzgrdz3fxyowrx1pq6dkva4nut.png)
![\text{ 2.5x + 4(}2400\text{ - x) = }$7140$](https://img.qammunity.org/2023/formulas/mathematics/high-school/jjuah29tr7f2nguenvlbi550igg695y8av.png)
![\text{ 2.5x + 9600 - 4x = }$7140$](https://img.qammunity.org/2023/formulas/mathematics/high-school/a7tc3hmg7pxe6byxfz312e1rsksynelalg.png)
![\text{ 2.5x - 4x = }$7140$\text{ - 9600 }](https://img.qammunity.org/2023/formulas/mathematics/high-school/kpllr5kotfsn8gmp2qw9xo0wrv0wfnw08l.png)
![\text{ -1.5x }=\text{ }-2,460](https://img.qammunity.org/2023/formulas/mathematics/high-school/3y1i5yqd6ff7f3gfdxx48dy8bwhx49oeam.png)
![\text{ }\frac{\text{-1.5x}}{-1.5}\text{ }=\text{ }(-2,460)/(-1.5)](https://img.qammunity.org/2023/formulas/mathematics/high-school/gmifbjhflvs7s7rw3j759odbabohkeewk1.png)
![\text{ x }=\text{ }1,640\text{ children}](https://img.qammunity.org/2023/formulas/mathematics/high-school/o39l19cicq8ynvq9zfkevv02yn3p2c3yqv.png)
Therefore, 1,640 children went to the fair.
For the adults,
x + y = 2400
1,640 + y = 2400
y = 2400 - 1,640
y = 760 adults
In summary: 1,640 children and 760 adults went to the fair.