15. A Ferris wheel is constructed such that a person gets on the wheel at its lowest point, 15 feet above the ground, and reaches its highest point at 165 feet above the ground. The amount of time it takes to complete one full rotation
is equal to 20 minutes. A person's vertical position, y, can be modeled as a function of time in minutes since they boarded, 1, by the equation y = Acos(Bt) +C. Sketch a graph of a person's vertical position for one cycle and then determine the values of A, B, and C. Show the work needed to arrive at your answers.