a. The probability that a student will receive an A,B,C or D grade is 0.40, 0.35, 0.15 and 0.10 respectively. Find the probability that a student will receive:
(i) not an A grade(ii) at most a C grade
(iii) B or C grade.
b. Neelam is taking up subjects Mathematics Physics and Chemistry. She estimates that her probabilities of receiving a grade A in these courses, are 0.2, 0.3 and 0.9 respectively. If the grades can be regarded as independent events, find the probabilities that Neelam receives,
(i) All A,'s (ii) NO A's
(iii) Exactly two A's

Answer

(a)(i) `0.60 (ii) 0.25 (iii) 0.50
b. (i) 0.054 (ii) 0.056 (iii) 0.38