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Chapter 13 Class 12 Probability
Example 6
Ex 13.1, 10 (a) Important
Ex 13.1, 12 Important
Example 11 Important
Ex 13.2, 7 Important
Ex 13.2, 11 (i)
Ex 13.2, 14 Important
Example 17 Important
Example 18 Important
Example 20 Important You are here
Example 21 Important
Ex 13.3, 2 Important
Ex 13.3, 4 Important
Ex 13.3, 8 Important
Ex 13.3, 10 Important
Ex 13.3, 12 Important
Ex 13.3, 13 (MCQ) Important
Question 4 Important Deleted for CBSE Board 2024 Exams
Question 5 Important Deleted for CBSE Board 2024 Exams
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Question 7 Important Deleted for CBSE Board 2024 Exams
Question 8 Important Deleted for CBSE Board 2024 Exams
Question 3 Important Deleted for CBSE Board 2024 Exams
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Question 15 Deleted for CBSE Board 2024 Exams
Question 10 Important Deleted for CBSE Board 2024 Exams
Question 11 Important Deleted for CBSE Board 2024 Exams
Question 4 Important Deleted for CBSE Board 2024 Exams
Question 6 Important Deleted for CBSE Board 2024 Exams
Question 10 Important Deleted for CBSE Board 2024 Exams
Question 13 Important Deleted for CBSE Board 2024 Exams
Question 13 Deleted for CBSE Board 2024 Exams
Example 23 Important
Question 2 Important Deleted for CBSE Board 2024 Exams
Question 4 Deleted for CBSE Board 2024 Exams
Question 6 Important Deleted for CBSE Board 2024 Exams
Misc 7 Important
Misc 10 Important
Chapter 13 Class 12 Probability
Last updated at May 29, 2023 by Teachoo
Example 20 A doctor is to visit a patient. From the past experience, it is known that the probabilities that he will come by train, bus, scooter or by other means of transport are respectively 3/10 , 1/5 , 1/10 and 2/5 . The probabilities that he will be late are 1/4 , 1/3 and 1/12 if he comes by train, bus and scooter respectively, but if he comes by other means of transport, then he will not be late. When he arrives, he is late. What is the probability that he comes by train?Let T1 : Event that doctor came by Train T2 : Event that doctor came by Bus T3 : Event that doctor came by Scooter T4 : Event that doctor came by other means of transport L : Event that doctor arrives late We need to find out Probability of doctor comes by train if he is late i.e. P(T1|L) =(𝑃(𝑇1) × 𝑃(𝐿|𝑇1))/(𝑃(𝑇1) × 𝑃(𝐿|𝑇1) + 𝑃(𝑇2) × 𝑃(𝐿|𝑇2) + 𝑃(𝑇3) × 𝑃(𝐿|𝑇3) + 𝑃(𝑇4) × 𝑃(𝐿|𝑇4)) P(T1) = Probability that doctor comes by train = 𝟑/𝟏𝟎 P(L|T1) = Probability that doctor comes late if he comes by train = 𝟏/𝟒 P(T2) = Probability that doctor comes by bus = 𝟏/𝟓 P(L|T2) = Probability that doctor comes late if he comes by bus = 𝟏/𝟑 P(T3) = Probability that doctor comes by scooter = 𝟏/𝟏𝟎 P(L|T3) = Probability that doctor comes late if he comes by scooter = 𝟏/𝟏𝟐 P(T4) = Probability that doctor comes by other means of transport = 𝟐/𝟓 P(L|T4) = Probability that doctor comes late if he comes by other means of transport = 𝟎 Putting values in formula, P(T1|L) =(𝑃(𝑇1) × 𝑃(𝐿|𝑇1))/(𝑃(𝑇1) × 𝑃(𝐿|𝑇1) + 𝑃(𝑇1) × 𝑃(𝐿|𝑇1) + 𝑃(𝑇1) × 𝑃(𝐿|𝑇1) + 𝑃(𝑇1) × 𝑃(𝐿|𝑇1)) = (3/(10 ) × 1/4)/( 3/(10 ) × 1/4 + 1/(5 ) × 1/3 + 1/(10 ) × 1/12 + 2/(5 ) × 0 ) =(3/( 40 ) )/( 18/(120 ) ) = 3/40×120/18 =360/720 = 𝟏/𝟐