The Probability of Student Grades

What is the probability that a student will receive at least a C grade?

A. 0.65

B. 0.85

C. 0.80

D. 0.20

Answer:

The correct option is B. The probability that a student will receive at least a C grade is 0.85.

Given that the probabilities of a student obtaining grades A, B, C, or D are 0.30, 0.35, 0.20, and 0.15 respectively, we can calculate the probability of receiving at least a C grade by adding the probabilities of grades A, B, and C.

Probability of getting an A: 0.30

Probability of getting a B: 0.35

Probability of getting a C: 0.20

Adding these probabilities together gives us:

0.30 (A) + 0.35 (B) + 0.20 (C) = 0.85

Therefore, the probability that a student will receive at least a C grade is 0.85, which corresponds to option B.