Araceli recently competed in a 10K race that had a mean finish time of = 63.3 minutes and standard deviation = 10.1 minutes. The finish times were approximately normally distributed.

If Araceli's finish time was 51.8 minutes,

a) Calculate the z-score for her time.

b) What percentage of runners had a faster finish time?

c) If she would like to finish in the top 10%, how much faster would she need to complete the race?