Water is filling a swimming pool at a constant rate. After 4 hours, 2 inches of water have filled the pool. Write an equation that gives the amount of water, w, after t hours.

Step-by-step explanation:

Inches per hour is the rate we are looking for here, which will then be the slope of the linear equation. Slope is the same thing as the rate of change. While this may not seem all that important right now, it's actually a HUGE concept in higher math, especially calculus!

If the pool is filling at a rate of 2 inches per every 4 hours, then by dividing, we get that the rate is 1 inch every 2 hours, which translates to a slope of 1/2. Creating an equation with this slope:

 Let's check it. We are told that after 4 hours there are 2 inches of water in the pool. That means if we plug in 4 for t and solve for w, we should get w = 2:

and

w = 2. So we're good!