Marguerite earned scores between 75 and 89 on all her previous spelling tests. She earned a score of 100 on her next test. Which of the following statements is true?

This the full question and according to me the correct answer is b.)

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."

it's undefined because anything multiplied by 0 is 0. that said, 7 days is 168 hours