Irum is sitting on the beach, watching the tide go in and out. Irum's distance from the shoreline (in meters) as a function of time (in hours) is graphed.
What is the approximate average rate at which Irum's distance from the shoreline increases, between the 9^\text{th}9
th
9, start superscript, start text, t, h, end text, end superscript and the 13^\text{th}13
th
13, start superscript, start text, t, h, end text, end superscript hour marks?