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WBJEE · Maths · Probability

A person goes to office by car, scooter, bus and train, probability of which are \(1 / 7,3 / 7\). \(2 / 7\) and \(1 / 7,\) respectively. Probability that he reaches office late, if he takes car, scooter, bus or train is \(2 / 9,1 / 9,4 / 9,\) and \(1 / 9,\) respectively. Given that he reached office in time, the probability that he travelled by a car, is

  1. A \(1 / 7\)
  2. B \(2 / 7\)
  3. C \(3 / 7\)
  4. D \(4 / 7\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(1 / 7\)

Step-by-step Solution

Detailed explanation

Let the event of person goes to office by a car, scooter, bus or train be \(A, B, C\) and \(D,\) respectively. We have, \(P(A)=\frac{1}{7}, P(B)=\frac{3}{7}, P(C)=\frac{2}{7}\) and \(P(D)=\frac{1}{7}\) Let \(E=\) He reached office in time We have…