After the booster club sold 40 hot dogs at a football game, it had $90 in profit. After the next game, it had sold a total of 80 hot dogs and had a total of $21
Question
2 Answer

1. User Answers leiinmain
The correct answer would be: y90=3(x40) 
2. User Answers tardymanchester
Answer:
Required equation [tex]y = 3x30[/tex]
Stepbystep explanation:
Given : After the booster club sold 40 hot dogs at a football game, it had $90 in profit. After the next game, it had sold a total of 80 hot dogs and had a total of $210 in profit.
To find : Which equation models the total profit,y,based on the number of hot dogs sold,x ?
Solution :
Let x = total number of hot dogs sold
y = total profit from total sales of hot dogs
We can model the equation: [tex]y = m x + b[/tex] ......[A]
where, y is the total profit and x is the number of hot dogs sold.
Profit for 40 hot dogs = $90 profit
The system of equation form is
[tex]90 =40m + b[/tex] ......[1]
Profit for 80 hot dogs = $210 profit
The system of equation form is
[tex]210 =80m + b[/tex] .......[2]
The solution of equations [1] and [2]
Subtract equation [1] and [2]
[tex]21090 = 80m40m + bb[/tex]
[tex]120 = 40m[/tex]
[tex]\frac{120}{40} = m[/tex]
[tex]3 = m[/tex]
Substitute in equation [1]
[tex]90 =40(3) + b[/tex]
[tex]90 =120+ b[/tex]
[tex]b=30[/tex]
Substitute the values in equation [A]
[tex]y = 3x30[/tex]
This is the required equation models the total profit based on number of hot dogs.