MATH 110 MODULE 3: PROBABILITY
AND PROBABILITY DISTRIBUTIONS
2026/2027 UPDATE. JUST RELEASED
1. If events A and B are mutually exclusive, which of the following must be true?
A. P(A and B) = P(A) * P(B)
B. P(A | B) = P(A)
C. P(A or B) = P(A) * P(B)
D. P(A and B) = 0
Answer: D
Conceptual Explanation: Mutually exclusive events cannot occur at the same time,
therefore the probability of their intersection is zero.
2. Which rule is used to calculate the probability of the union of two events that are not
mutually exclusive?
A. P(A or B) = P(A) + P(B)
B. P(A or B) = P(A) * P(B)
C. P(A or B) = P(A) / P(B)
D. P(A or B) = P(A) + P(B) - P(A and B)
,Answer: D
Conceptual Explanation: The General Addition Rule subtracts the intersection to avoid
double-counting outcomes that belong to both events.
3. If P(A) = 0.4 and P(B) = 0.5, and A and B are independent, what is P(A and B)?
A. 0.2
B. 0.1
C. 0.9
D. 0.0
Answer: A
Conceptual Explanation: For independent events, P(A and B) = P(A) * P(B) = 0.4 * 0.5 =
0.2.
4. The probability of an event and its complement always sums to:
A. 0.5
B. 0.0
C. 1.0
D. Depends on the sample space
Answer: C
, Conceptual Explanation: An event and its complement cover all possible outcomes in the
sample space, so their sum is always 1.
5. What is the formula for the conditional probability P(A | B)?
A. P(A and B) / P(A)
B. P(A and B) / P(B)
C. P(A) / P(B)
D. P(A) + P(B)
Answer: B
Conceptual Explanation: Conditional probability is the probability of A occurring given
that B has already occurred, calculated as the intersection divided by the given event.
6. In a permutation, which of the following is true?
A. Order matters
B. Items are replaced after selection
C. Order does not matter
D. Only two outcomes are possible
Answer: A
Conceptual Explanation: Permutations refer to the arrangement of items where the
specific sequence or order is important.
AND PROBABILITY DISTRIBUTIONS
2026/2027 UPDATE. JUST RELEASED
1. If events A and B are mutually exclusive, which of the following must be true?
A. P(A and B) = P(A) * P(B)
B. P(A | B) = P(A)
C. P(A or B) = P(A) * P(B)
D. P(A and B) = 0
Answer: D
Conceptual Explanation: Mutually exclusive events cannot occur at the same time,
therefore the probability of their intersection is zero.
2. Which rule is used to calculate the probability of the union of two events that are not
mutually exclusive?
A. P(A or B) = P(A) + P(B)
B. P(A or B) = P(A) * P(B)
C. P(A or B) = P(A) / P(B)
D. P(A or B) = P(A) + P(B) - P(A and B)
,Answer: D
Conceptual Explanation: The General Addition Rule subtracts the intersection to avoid
double-counting outcomes that belong to both events.
3. If P(A) = 0.4 and P(B) = 0.5, and A and B are independent, what is P(A and B)?
A. 0.2
B. 0.1
C. 0.9
D. 0.0
Answer: A
Conceptual Explanation: For independent events, P(A and B) = P(A) * P(B) = 0.4 * 0.5 =
0.2.
4. The probability of an event and its complement always sums to:
A. 0.5
B. 0.0
C. 1.0
D. Depends on the sample space
Answer: C
, Conceptual Explanation: An event and its complement cover all possible outcomes in the
sample space, so their sum is always 1.
5. What is the formula for the conditional probability P(A | B)?
A. P(A and B) / P(A)
B. P(A and B) / P(B)
C. P(A) / P(B)
D. P(A) + P(B)
Answer: B
Conceptual Explanation: Conditional probability is the probability of A occurring given
that B has already occurred, calculated as the intersection divided by the given event.
6. In a permutation, which of the following is true?
A. Order matters
B. Items are replaced after selection
C. Order does not matter
D. Only two outcomes are possible
Answer: A
Conceptual Explanation: Permutations refer to the arrangement of items where the
specific sequence or order is important.
