There were 680 gallons of water ALREADY in a 1600-gallon pool. Water is being pumped into the pool at the rate of 320 gallons per hour. Let x represents the number of hours. Find how many hours it will take to fill the pool.

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.