Question

In a math class, the distribution of grades was as follows: Grade A B C D F Number of students 6 13 9 4 2 If we select a student at random (Grade A-6 students)(Grade B-13 students)(Grade C-9 students) (Grade D-4 students)(Grade F-2 students)

(a) What is the probability that the student will have at least a C in the class?

(b) What is the probability that the student will have an A in the class, if it is known that the student has at least a C?

Answer 1

a) 14/17

b) 3/14

Explanation:

6+13+9+4+2 = 34

a) P( C or better ) = (6+13+9)/34

= 28/35 = 14/17

b) P( A/C or better ) = 6/28 = 3/14