A car travels 180 miles using 6 gallons of gasoline. What is the constant of proportionality?

1. A car travels 180 miles using 6 gallons of gasoline. What is the constant of proportionality?
2. Explain what the constant of proportionality means in Question 1.
3. Two students are solving this problem:
A recipe uses 4 cups of flour for every 5 cups of sugar. Student A says the constant of proportionality is 4/5. Student B says the constant of proportionality is 1.25. Who is correct if flour is (x) and sugar is (y)?
Explain.
4. What is the constant of proportionality for the relationship in Question 3?