Answer
a) $r \gt 5.71$
b) No
Work Step by Step
a) The speed of the runner is obtained by dividing the distance with time.
Speed of the runner is $\frac{200}{35}$ which is approximately equal to $5.71$ meters per second. For any speed faster than the runner, the inequality will be $$r \gt 5.71.$$ In the graph, all numbers to the right of $5.71$ are marked with an open circle at $5.71$.
b) No, the number line extends to infinity. At some point in the number line, there will be speed which is physically unattainable by the human body. Hence not all numbers on the graph can be a runner's speed.
