Final answer:
To find the value of M when P = 9, we can use the concept of direct proportionality and the formula M = kP.
Step-by-step explanation:
To solve this problem, we can use the concept of direct proportionality. If M is directly proportional to P, it means that as P increases, M also increases and vice versa. We can use the formula M = kP, where k is the constant of proportionality.
Given that M = 15 when P = 45, we can substitute these values into the equation: 15 = k * 45. Solving for k, we divide both sides by 45: k = 15/45 = 1/3.
Now we can find M when P = 9 by substituting the value of P into the equation: M = (1/3) * 9 = 3.