Sarah is filling an empty aquarium at a constant rate of 4 gallons per minute. The total number of gallons Sarah adds to the aquarium is a function of the time in minutes.

Question

We can represent this situation in different ways like an equation, a graph, or a table. Let’s start with an equation. What do the variables x and y represent in this situation?
y = 4 ⋅ x
= gallons per minute ⋅

Answer 1

In this situation, we can define the variables in the equation \( y = 4 \cdot x \) as follows:

• \( x \): This variable represents the time in minutes that have passed while Sarah is filling the aquarium.
• \( y \): This variable represents the total number of gallons of water that have been added to the aquarium after \( x \) minutes.

So, the equation \( y = 4 \cdot x \) states that the total gallons of water \( y \) added to the aquarium is equal to the rate at which Sarah fills the aquarium (4 gallons per minute) multiplied by the time in minutes \( x \).