The perimeter p of a square (measured in inches) is expanding in size at a constant rate of change of 4 inches per inch with respect to the square's side length s (measured in inches). if the length of the side of the square changes from:

a. 0 to 2.5 inches, how does the square's perimeter p change?
b. 1 to 3 inches, how does the square's perimeter p change?
c. express the change in the square's perimeter p in terms of the change in the square's side length s.