4. CONSTRUCTION Peyton is using a sledgehammer to drive fence posts into the ground. On his first swing, he
drives a post five inches into the ground. Since the soil is
denser the deeper he drives, on each swing after the
first, he can only drive the post 30% as far into the
ground as he did on the previous swing. How far has he
driven the post into the ground after five swings?

- "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."