The probabilities that a student will receive an A, B, C or D grade are 0.4, 0.3 , 0.2 and 0.1 respectively. Find the probability that a student will receive Atleast B grade.
A) 0.21
B) 0.3
C) 0.7
D) None of these
Answer: C) 0.7
Explanation:
P(atleast B) = P( B or A) = P(B) + P(A) = (0.3) + (0.4) = 0.7