Question

The x-axis represents time in minutes ranging from 0 to 16 in increments of 2. The vertical axis represents distance in miles ranging from 0 to 2 in increments of 0 point 2. A curve passes through the coordinates left parenthesis 0 comma 0 right parenthesis, left parenthesis 2 comma 0.4 right parenthesis, left parenthesis 8 comma 1 right parenthesis, and left parenthesis 11 comma 1 point 5 right parenthesis.

Riley is training to run a 5-mile race. The graph represents the distance (miles) she ran with respect to time (minutes) in her first training run. Over which time interval did she run the fastest, [0,8]
or [2,11]
? Justify your answer in 1–2 sentences.

(2 points)

Answer 1

Riley ran fastest on [0,8], because the average rate there is (1−0)/(8−0)=1/8=0.125 miles/min, which is slightly greater than the rate on [2,11], (1.5−0.4)/(11−2)=1.1/9≈0.122 miles/min.