Final answer:
The equation to model the relationship for Melissa's pay is p = 15m. The coefficient represents Melissa's hourly pay rate.
Step-by-step explanation:
The correct equation to model the relationship for Melissa's pay is p = 15m.
In this equation, the coefficient (constant of proportionality/unit rate) is 15.
The coefficient represents Melissa's hourly pay rate. This means that for every hour she works, she earns $15.