Verified Solution • 2025–26 Session moderate

QJEEM18Ma0198: JEE Main 2018 Mathematics - Class 12 JEEM18Ma0198 Solution: Let A, B and C be three events, which are pair-wise independent …

Let A, B and C be three events, which are pair-wise independent and E→\overrightarrow E denotes the completement of an event E. If P(A∩B∩C)=0P\left( {A \cap B \cap C} \right) = 0 and P\left( C \right) > 0, then P[(A‾∩B‾)∣C]P\left[ {\left( {\overline A \cap \overline B } \right)\left| C \right.} \right] is equal to :

Multiple Choice Options

  • A P(A‾)−P(B)P\left( {\overline A } \right) - P\left( B \right)
  • B P(A)+P(B‾)P\left( A \right) + P\left( {\overline B } \right)
  • C P(A‾)−P(B‾)P\left( {\overline A } \right) - P\left( {\overline B } \right)
  • D P(A‾)+P(B‾)P\left( {\overline A } \right) + P\left( {\overline B } \right)

Step-by-Step Verified Solution

Here, P(A‾∩B‾∣C)=P(A‾∩B‾∩C)P(C)P\left( {\overline A \cap \overline B \left| C \right.} \right) = {{P\left( {\overline A \cap \overline B \cap C} \right)} \over {P\left( C \right)}}

= P[(A∪B‾)∩C]P(C){{P\left[ {\left( {\overline {A \cup B} } \right) \cap C} \right]} \over {P\left( C \right)}}

= P[C−(A∪B)]P(C){{P\left[ {C - \left( {A \cup B} \right)} \right]} \over {P\left( C \right)}}

= P(C)−P(A∩C)−P(B∩C)+P(A∩B∩C)P(C){{P\left( C \right) - P\left( {A \cap C} \right) - P\left( {B \cap C} \right) + P\left( {A \cap B \cap C} \right)} \over {P\left( C \right)}}

= P(C)−P(A∩C)−P(B∩C)P(C){{P\left( C \right) - P\left( {A \cap C} \right) - P\left( {B \cap C} \right)} \over {P\left( C \right)}} ( ∵\because P(A∩B∩C)=0)\left. {P\left( {A \cap B \cap C} \right) = 0} \right)

= P(C)−P(A).P(C)−P(B).P(C)P(C){{P\left( C \right) - P\left( A \right).P(C) - P\left( B \right).P(C)} \over {P\left( C \right)}}

[ ∵\because A, B and C are independent events]

= 1 - P(A) - P(B)

= P(A‾)P\left( {\overline A } \right) - P(B) or P(B‾)P\left( {\overline B } \right) - P(A)

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