22. For each of the following, identify the exam score that should lead to the better grade. In each case, explain your answer.

a. A score of X = 56, on an exam with 50 and

 4, or a score of X = 60 on an exam with 50 and  20.

b A score of X = 40, on an exam with 45 and

 2, or a score of X = 60 on an exam with 70 and  20.

c. A score of X = 62, on an exam with 50 and

 8, or a score of X = 23 on an exam with 20 and  2.