An energetic student can manage to get 9 sled runs down a hill, on average, within a

Question:

An energetic student can manage to get 9 sled runs down a hill, on average, within a 30 minute time period.
a. Find an upper bound on the probability that the student achieves 12 or more runs during a one hour period.
b. If the standard deviation of the number of runs that they can manage in a 30 minute period is 2, then give a bound on the probability that the student gets between 6 and 12 sled runs during a 30 minute period.