Please Help, I do not have much time! A series of locks manages the water height along a water source used to produce energy. As the locks are opened and closed, the water height between two consecutive locks fluctuates.

The height of the water at point B located between two locks is observed. Water height measurements are made every 10 minutes beginning at 8:00 a. m.

It is determined that the height of the water at B can be modeled by the function f(x)=−11cos(πx/48 − 5π/12)+28 , where the height of water is measured in feet and x is measured in minutes.

What is the maximum and minimum water height at B, and when do these heights first occur?