A bottler of drinking water fills plastic bottles with a mean volume of 993 milliliters (mL) and standard deviation of 8 mL. The fill volumes are normally distributed. What proportion of bottles have volumes between 991 mL and 997 mL?

- "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."

i believe that the answer is

b. y-1=-2(x-4)

hope this !