Identify Constant of Proportionality Practice Test

A scientist observes that a bacterial culture grows proportionally over time. The equation $$P = 150t$$ represents the relationship, where $$P$$ is the population and $$t$$ is time in hours. However, the scientist notes that the initial population was actually 50 bacteria that were not accounted for in this growth model. What is the constant of proportionality for the growth rate?

A water tank fills at a constant rate. In the first 4 minutes, 18 gallons flow into the tank. In the next 6 minutes, 27 gallons flow into the tank. What is the constant of proportionality that describes gallons per minute?