Final answer:
To write the equation, determine the constant of proportionality, which is 6 muffins per cup of flour. The equation is y = 6x, where y represents the number of muffins and x represents the volume of flour in cups.
Step-by-step explanation:
To write the equation for the relationship between the volume of flour, x, and the number of muffins, y, you need to determine the constant of proportionality. In this case, Darrell can bake 6 muffins using 1 cup of flour. So, the constant of proportionality is 6 muffins per cup of flour.
The equation for the relationship between x and y is: y = 6x
Where y represents the number of muffins and x represents the volume of flour in cups.