When Jack turned 21, he decided to start investing $200 a month every year for nine years. At age 30, he decided to stop investing altogether. Blake started a little later, investing $200 a month every month starting at age 30, all the way until the ripe old age of 67.
Assuming that they were both amazing at investing and made 11% interest per year, how much money will they both have at age 67?
Also, what surprised you about this? What was important about this question?

step-by-step explanation:

- "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."