Question:

If \(A\), \(B\), \(C\) are independent events of a random experiment such that \[ P(A)=\frac34,\qquad P(B)=\frac56,\qquad P(C)=\frac23, \] then the probability that exactly one of the events occurs is

Show Hint

For independent events, "exactly one occurs" means: \[ A B^c C^c \quad \text{or} \quad A^c B C^c \quad \text{or} \quad A^c B^c C. \] Find each probability separately and then add them.
Updated On: Jul 9, 2026
  • \(\dfrac14\)
  • \(\dfrac{5}{36}\)
  • \(\dfrac{5}{12}\)
  • \(\dfrac{71}{72}\) \bigskip
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

Concept: For independent events, the probability that exactly one event occurs is the sum of the probabilities of the following mutually exclusive cases: \[ A\cap B^c\cap C^c, \] \[ A^c\cap B\cap C^c, \] \[ A^c\cap B^c\cap C. \] Also, \[ P(A^c)=1-P(A). \]

Step 1:
Find the probabilities of the complementary events. \[ P(A^c)=1-\frac34=\frac14, \] \[ P(B^c)=1-\frac56=\frac16, \] \[ P(C^c)=1-\frac23=\frac13. \]

Step 2:
Find the probability that only \(A\) occurs. Since the events are independent, \[ P(A\cap B^c\cap C^c) = P(A)P(B^c)P(C^c). \] \[ = \frac34\cdot\frac16\cdot\frac13. \] \[ = \frac1{24}. \]

Step 3:
Find the probability that only \(B\) occurs. \[ P(A^c\cap B\cap C^c) = P(A^c)P(B)P(C^c). \] \[ = \frac14\cdot\frac56\cdot\frac13. \] \[ = \frac5{72}. \]

Step 4:
Find the probability that only \(C\) occurs. \[ P(A^c\cap B^c\cap C) = P(A^c)P(B^c)P(C). \] \[ = \frac14\cdot\frac16\cdot\frac23. \] \[ = \frac1{36}. \]

Step 5:
Add the three mutually exclusive cases. \[ P(\text{exactly one event occurs}) = \frac1{24} + \frac5{72} + \frac1{36}. \] Taking LCM \(=72\), \[ = \frac3{72} + \frac5{72} + \frac2{72}. \] \[ = \frac{10}{72}. \] \[ = \frac5{36}. \]

Step 6:
Write the final answer. \[ \boxed{\frac5{36}} \]
Was this answer helpful?
0
0