Skip to main contentSkip to solution

If A and B are independent events, then which of the following statements are TRUE?

(A) P(AB)=P(A).P(B)P(A \cap B) = P(A).P(B)

(B) P(AB)=P(A)P(B)P(A \cap B) = P(A) - P(B)

(C) P(AB)=P(A)+P(B)P(A).P(B)P(A \cup B) = P(A) + P(B) - P(A).P(B)

(D) P(AB)=P(A).P(BA)P(A \cap B) = P(A). P(B|A)

Choose the correct answer from the options given below:

Solution

Correct Option: 4

For two independent events A and B, one event happening doesn't affect the probability of the other.

The key formula for independent events:

P(AB)=P(A)×P(B)P(A \cap B) = P(A) \times P(B)


Statement (A): P(AB)=P(A).P(B)P(A \cap B) = P(A).P(B)

This is the definition of independent events.

Statement (A) is TRUE.


Statement (B): P(AB)=P(A)P(B)P(A \cap B) = P(A) - P(B)

If P(A)=0.3P(A) = 0.3 and P(B)=0.5P(B) = 0.5:

P(AB)=0.30.5=0.2P(A \cap B) = 0.3 - 0.5 = -0.2

Probability cannot be negative.

Statement (B) is FALSE.


Statement (C): P(AB)=P(A)+P(B)P(A).P(B)P(A \cup B) = P(A) + P(B) - P(A).P(B)

The general union formula:

P(AB)=P(A)+P(B)P(AB)P(A \cup B) = P(A) + P(B) - P(A \cap B)

For independent events, P(AB)=P(A)×P(B)P(A \cap B) = P(A) \times P(B)

Substituting:

P(AB)=P(A)+P(B)P(A)×P(B)P(A \cup B) = P(A) + P(B) - P(A) \times P(B)

Statement (C) is TRUE.


Statement (D): P(AB)=P(A).P(BA)P(A \cap B) = P(A). P(B|A)

The general multiplication formula (always valid):

P(AB)=P(A)×P(BA)P(A \cap B) = P(A) \times P(B|A)

For independent events, P(BA)=P(B)P(B|A) = P(B) since A doesn't affect B.

Therefore:

P(AB)=P(A)×P(BA)P(A \cap B) = P(A) \times P(B|A)

P(AB)=P(A)×P(B)P(A \cap B) = P(A) \times P(B)

Statement (D) is TRUE.


Statements (A), (C), and (D) are TRUE.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question