please answer this and ill rate you.

The following are the scores of 20 students who took the qualifying exam for a majoring course. 65 88 56 96 78 77 79 99 66 75 88 89 78 95 91 81 80 60 68 77 a. If only the top 25% can qualify for the majoring course , then what is the cut-off score ? b. Student who got scores below the Ist quartile could not re-take the exam. What is the cut-off score for students who can re-take the exam