## Step 1: Define the symbolic representation of the variables
The variables are: ravioli, ham sandwiches, blueberry pies, pickles, sashimi.
Let's denote them as: x1, x2, x3, x4, x5 respectively.

## Step 2: Convert the objective function into a symbolic representation
The objective function to minimize is: $6.4x_1 + 3.16x_2 + 8.42x_3 + 5.54x_4 + 1.86x_5$.

## 3: List the constraints in symbolic notation
1. $20x_1 + 19x_2 + 11x_3 + 13x_4 + 12x_5 \leq 145$
2. $11x_3 + 13x_4 \geq 16$
3. $19x_2 + 13x_4 \geq 20$
4. $20x_1 + 13x_4 + 12x_5 \geq 17$
5. $19x_2 + 11x_3 + 13x_4 \geq 17$
6. $19x_2 + 11x_3 + 12x_5 \geq 17$
7. $20x_1 + 19x_2 + 13x_4 \geq 17$
8. $20x_1 + 11x_3 + 13x_4 \geq 17$
9. $11x_3 + 13x_4 + 12x_5 \geq 17$
10. $20x_1 + 13x_4 + 12x_5 \geq 15$
11. $19x_2 + 11x_3 + 13x_4 \geq 15$
12. $19x_2 + 11x_3 + 12x_5 \geq 15$
13. $20x_1 + 19x_2 + 13x_4 \geq 15$
14. $20x_1 + 11x_3 + 13x_4 \geq 15$
15. $11x_3 + 13x_4 + 12x_5 \geq 15$
16. $20x_1 + 13x_4 + 12x_5 \geq 17$
17. $19x_2 + 11x_3 + 13x_4 \geq 17$
18. $19x_2 + 11x_3 + 12x_5 \geq 17$
19. $20x_1 + 19x_2 + 13x_4 \geq 17$
20. $20x_1 + 11x_3 + 13x_4 \geq 17$
21. $11x_3 + 13x_4 + 12x_5 \geq 17$
22. $20x_1 + 13x_4 + 12x_5 \geq 19$
23. $19x_2 + 11x_3 + 13x_4 \geq 19$
24. $19x_2 + 11x_3 + 12x_5 \geq 19$
25. $20x_1 + 19x_2 + 13x_4 \geq 19$
26. $20x_1 + 11x_3 + 13x_4 \geq 19$
27. $11x_3 + 13x_4 + 12x_5 \geq 19$
28. $20x_1 + 13x_4 + 12x_5 \geq 28$
29. $19x_2 + 11x_3 + 13x_4 \geq 28$
30. $19x_2 + 11x_3 + 12x_5 \geq 28$
31. $20x_1 + 19x_2 + 13x_4 \geq 28$
32. $20x_1 + 11x_3 + 13x_4 \geq 28$
33. $11x_3 + 13x_4 + 12x_5 \geq 28$
34. $20x_1 + 19x_2 + 11x_3 + 13x_4 + 12x_5 \geq 28$
35. $-8x_1 + 7x_3 \geq 0$
36. $8x_1 - 4x_5 \geq 0$
37. $13x_4 + 12x_5 \leq 136$

## 4: Define the symbolic representation of the problem
```json
{
    'sym_variables': [
        ('x1', 'ravioli'), 
        ('x2', 'ham sandwiches'), 
        ('x3', 'blueberry pies'), 
        ('x4', 'pickles'), 
        ('x5', 'sashimi')
    ], 
    'objective_function': '6.4*x1 + 3.16*x2 + 8.42*x3 + 5.54*x4 + 1.86*x5', 
    'constraints': [
        '20*x1 + 19*x2 + 11*x3 + 13*x4 + 12*x5 <= 145',
        '11*x3 + 13*x4 >= 16',
        '19*x2 + 13*x4 >= 20',
        '20*x1 + 13*x4 + 12*x5 >= 17',
        '19*x2 + 11*x3 + 13*x4 >= 17',
        '19*x2 + 11*x3 + 12*x5 >= 17',
        '20*x1 + 19*x2 + 13*x4 >= 17',
        '20*x1 + 11*x3 + 13*x4 >= 17',
        '11*x3 + 13*x4 + 12*x5 >= 17',
        '20*x1 + 13*x4 + 12*x5 >= 15',
        '19*x2 + 11*x3 + 13*x4 >= 15',
        '19*x2 + 11*x3 + 12*x5 >= 15',
        '20*x1 + 19*x2 + 13*x4 >= 15',
        '20*x1 + 11*x3 + 13*x4 >= 15',
        '11*x3 + 13*x4 + 12*x5 >= 15',
        '20*x1 + 13*x4 + 12*x5 >= 17',
        '19*x2 + 11*x3 + 13*x4 >= 17',
        '19*x2 + 11*x3 + 12*x5 >= 17',
        '20*x1 + 19*x2 + 13*x4 >= 17',
        '20*x1 + 11*x3 + 13*x4 >= 17',
        '11*x3 + 13*x4 + 12*x5 >= 17',
        '20*x1 + 13*x4 + 12*x5 >= 19',
        '19*x2 + 11*x3 + 13*x4 >= 19',
        '19*x2 + 11*x3 + 12*x5 >= 19',
        '20*x1 + 19*x2 + 13*x4 >= 19',
        '20*x1 + 11*x3 + 13*x4 >= 19',
        '11*x3 + 13*x4 + 12*x5 >= 19',
        '20*x1 + 13*x4 + 12*x5 >= 28',
        '19*x2 + 11*x3 + 13*x4 >= 28',
        '19*x2 + 11*x3 + 12*x5 >= 28',
        '20*x1 + 19*x2 + 13*x4 >= 28',
        '20*x1 + 11*x3 + 13*x4 >= 28',
        '11*x3 + 13*x4 + 12*x5 >= 28',
        '20*x1 + 19*x2 + 11*x3 + 13*x4 + 12*x5 >= 28',
        '-8*x1 + 7*x3 >= 0',
        '8*x1 - 4*x5 >= 0',
        '13*x4 + 12*x5 <= 136'
    ]
}
```

## 5: Write the Gurobi code
```python
import gurobi

# Create a new model
m = gurobi.Model()

# Define the variables
x1 = m.addVar(name="ravioli", lb=-gurobi.GRB.INFINITY)
x2 = m.addVar(name="ham sandwiches", lb=-gurobi.GRB.INFINITY)
x3 = m.addVar(name="blueberry pies", lb=-gurobi.GRB.INFINITY)
x4 = m.addVar(name="pickles", lb=-gurobi.GRB.INFINITY)
x5 = m.addVar(name="sashimi", lb=-gurobi.GRB.INFINITY)

# Define the objective function
m.setObjective(6.4 * x1 + 3.16 * x2 + 8.42 * x3 + 5.54 * x4 + 1.86 * x5, gurobi.GRB.MINIMIZE)

# Add constraints
m.addConstr(20 * x1 + 19 * x2 + 11 * x3 + 13 * x4 + 12 * x5 <= 145)
m.addConstr(11 * x3 + 13 * x4 >= 16)
m.addConstr(19 * x2 + 13 * x4 >= 20)
m.addConstr(20 * x1 + 13 * x4 + 12 * x5 >= 17)
m.addConstr(19 * x2 + 11 * x3 + 13 * x4 >= 17)
m.addConstr(19 * x2 + 11 * x3 + 12 * x5 >= 17)
m.addConstr(20 * x1 + 19 * x2 + 13 * x4 >= 17)
m.addConstr(20 * x1 + 11 * x3 + 13 * x4 >= 17)
m.addConstr(11 * x3 + 13 * x4 + 12 * x5 >= 17)
m.addConstr(20 * x1 + 13 * x4 + 12 * x5 >= 15)
m.addConstr(19 * x2 + 11 * x3 + 13 * x4 >= 15)
m.addConstr(19 * x2 + 11 * x3 + 12 * x5 >= 15)
m.addConstr(20 * x1 + 19 * x2 + 13 * x4 >= 15)
m.addConstr(20 * x1 + 11 * x3 + 13 * x4 >= 15)
m.addConstr(11 * x3 + 13 * x4 + 12 * x5 >= 15)
m.addConstr(20 * x1 + 13 * x4 + 12 * x5 >= 17)
m.addConstr(19 * x2 + 11 * x3 + 13 * x4 >= 17)
m.addConstr(19 * x2 + 11 * x3 + 12 * x5 >= 17)
m.addConstr(20 * x1 + 19 * x2 + 13 * x4 >= 17)
m.addConstr(20 * x1 + 11 * x3 + 13 * x4 >= 17)
m.addConstr(11 * x3 + 13 * x4 + 12 * x5 >= 17)
m.addConstr(20 * x1 + 13 * x4 + 12 * x5 >= 19)
m.addConstr(19 * x2 + 11 * x3 + 13 * x4 >= 19)
m.addConstr(19 * x2 + 11 * x3 + 12 * x5 >= 19)
m.addConstr(20 * x1 + 19 * x2 + 13 * x4 >= 19)
m.addConstr(20 * x1 + 11 * x3 + 13 * x4 >= 19)
m.addConstr(11 * x3 + 13 * x4 + 12 * x5 >= 19)
m.addConstr(20 * x1 + 13 * x4 + 12 * x5 >= 28)
m.addConstr(19 * x2 + 11 * x3 + 13 * x4 >= 28)
m.addConstr(19 * x2 + 11 * x3 + 12 * x5 >= 28)
m.addConstr(20 * x1 + 19 * x2 + 13 * x4 >= 28)
m.addConstr(20 * x1 + 11 * x3 + 13 * x4 >= 28)
m.addConstr(11 * x3 + 13 * x4 + 12 * x5 >= 28)
m.addConstr(20 * x1 + 19 * x2 + 11 * x3 + 13 * x4 + 12 * x5 >= 28)
m.addConstr(-8 * x1 + 7 * x3 >= 0)
m.addConstr(8 * x1 - 4 * x5 >= 0)
m.addConstr(13 * x4 + 12 * x5 <= 136)

# Solve the model
m.optimize()

# Print the solution
if m.status == gurobi.GRB.OPTIMAL:
    print("Objective: ", m.objval)
    print("Ravioli: ", x1.varValue)
    print("Ham sandwiches: ", x2.varValue)
    print("Blueberry pies: ", x3.varValue)
    print("Pickles: ", x4.varValue)
    print("Sashimi: ", x5.varValue)
else:
    print("The model is infeasible")
```