2. Find the median of the set of numbers: 21, 3, 7, 17, 19, 31, 46, 20 and 43.

Step-by-step explanation:

The first step to finding the median is to sort the numbers from small to large.

3, 7, 17, 19, 20, 21, 31, 43, 46

then you find the middle number, equal numbers on other sides.

20 is in the middle because that leaves 4 on each side.

- "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."

6e14 is the answer.