Nineteen cards numbered from 1 through 19 are placed into a box and two cards are selected without replacement.
find the probability that both numbers selected are odd, given that their sum is even.
find the probability that both numbers selected are odd, given that their sum is even.

- "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."

answer is 270 degrees: -

to convert radians to degrees you multiply by 180/π

9π/ 6 * 180 / π

=   9 * 180 / 6

= 9 * 30

=   270 degrees   answer