Midterm exam marks in a computer science class are normally distributed with mean equals to 67 and standard deviation equals to 10.

6) The probability that a randomly selected student will obtain a mark between 60 and 75 is: a) 0.1089 b) 0.2420 c) 0.5461 d) 0.7881

7) The top 25% of students obtained marks higher than: a) 60.25 b) 73.75 c) 80.50 d) 65.7