Probability & Counting is one of 10 topics in the Grade 12 Mathematics CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. For any event A, P(not A) equals:
1 - P(A)
P(A) - 1
1 + P(A)
P(A)
Answer: 1 - P(A) — The complementary rule: the probability of an event not happening is 1 minus the probability that it does happen.
Easy
2. For independent events A and B, P(A and B) equals:
P(A) x P(B)
P(A) + P(B)
P(A) - P(B)
P(A) / P(B)
Answer: P(A) x P(B) — Independent events multiply: P(A and B)=P(A)×P(B).
Medium
3. Events A and B are mutually exclusive if:
P(A and B) = 0
P(A and B) = P(A) x P(B)
P(A or B) = P(A) x P(B)
P(A) = P(B)
Answer: P(A and B) = 0 — Mutually exclusive events cannot both happen at once, so their joint probability is 0, which is why P(A or B) simplifies to P(A)+P(B) for them.
