Given :
The cost to enter the park is $30.
The cost to enter with the meal plan is $45.
Total budget = $2700
The model of the total cost : 30x + 45y = 2700
x : is the number of the students who do not choose the meal plan
y : is the number of students who do choose the meal plan.
And the following graph represents the model of equation
a) As shown in the figure : y - intercept is the point ( 0 , 60 )
The y- intercept is the point at which x = 0
So, when x = 0 , y = 60
Which mean : the total number of the students at this case = 60 students
And all of them choose the meal plane
As the budget = $2700, the minimum number of the students can go the trip is 60
b) if 60 students do not choose meal plane , how many students did choose the meal plane?
60 students do no choose the meal plane. so, x = 60
To find the students who choose the meal plane, substitute with x = 60 at the give equation
OR can be calculated using the graph ,
at x = 60 , go up till the intersection with the line then go left to find the corresponding value of y as shown in the following figure :
So, y = 20
The answer is : the number of the students who choose the meal plane = 20 students