Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: Upto college level

In a test an examinee either guesses or copies or knows that answer to a multiple choice question which has 4 choices. The probability that he makes a guess is 1/3 and the probability that he copies is 1/6. The probability that his answer is correct, given the copied it, is 1/8. Find the probability that he knew the answer to the question, given that he answered it correctly.

11 years ago

Answers : (2)

Vijay Luxmi Askiitiansexpert
357 Points

P(g) = probability of guessing = 1/3

        P(c) = probability of copying = 1/6

        P(k) = probability of knowing = 1 - 1/3 - 1/6 = 1/2

        (Since the three-event g, c and k are mutually exclusive and exhaustive)

        P(w) = probability that answer is correct

       P(k/w)=(P(w/k).P(k))/(P(w/c)P(c)+P(w/k)P(k)+P(w/g)P(g))        (using Baye's theorem)

         = (1×1/2)/((1/8,1/6)+(1×1/2)+(1/4×1/3) )=24/29     

11 years ago
13 Points
P(w/c) can't be less than 1/4..As there are 4 choices to the multiple choice question and even if he copies from someone else's the minimum probability of getting a correct choice is greater than or equal to 1/4.
one year ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 731 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 101 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details