Question

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
\[9^\text{th}\] and the
\[13^\text{th}\] hour marks?
The first quadrant of a coordinate plane. The x-axis scales by one and is labeled time in hours. The y-axis scales by one and is labeled shoreline in meters. The graph is a continuous curve. It starts at the y-intercept zero, eight and increases at a non linear rate through the point one, ten until it reaches a local maximum at the point three, eleven. Then it decreases through the point five, nine point five and the point seven, seven until it reaches a local minimum at nine, six. Then it increases though the point twelve, eight and thirteen nine until reaching a local maximum at fifteen, ten. All values are estimates.
\[\small{2}\]
\[\small{4}\]
\[\small{6}\]
\[\small{8}\]
\[\small{10}\]
\[\small{12}\]
\[\small{14}\]
\[\small{2}\]
\[\small{4}\]
\[\small{6}\]
\[\small{8}\]
\[\small{10}\]
\[\small{12}\]
\[\small{14}\]
Choose 1 answer:
A
\[0.75\] meters per hour
B
\[1\] meter per hour
C
\[1.25\] meters per hour
D
\[1.5\] meters per hour

Answer 1

Average rate = (distance at 13 − distance at 9)/(13 − 9) = (9 − 6)/4 = 3/4 = 0.75 m/hour.
Answer: A.