This is the problem and the questions, i dont understand what equations im suppose to use or how to find the answer .

1.A developmental psychologist was interested in how long it would take a particular 7-year-old child to complete three different aptitude tests as compared with 7-year-olds in the general population. The child's time for reading was 31 minutes (population: M = 29, SD = 4). For math, it was 26 minutes (population: M = 32, SD = 2). For science, it was 40 minutes (population: M = 31, SD = 4).

a.Calculate the child's z- scores for each of the aptitude tests. (15 pts)

b.What proportion of the normal distribution corresponds to z-score values greater than the child's z-score on the science test.(5 pts)

c.Which aptitude test(s) took the child substantially more time to complete as compared with other 7-year-olds?(5 pts)