Given, Customers pay $4 to enter the pumpkin patch.
And also given, customers pay $3 per pound for the pumpkins.
Given, $y be the total cost and there are x pounds of pumpkins.
The cost for pumpkin per pound = $3.
Therefore, the cost for x pound pumpkins = $(3x)
As the total cost includes the payment for entering the patch also,
So the total cost y = 3x + 4
We have got the required equation.
The equation to model the total cost is y = 3x+4.