JEE Advanced2024MathematicsProbabilityActual
A student appears for a quiz consisting of only true-false type questions and answers all the questions. The student knows the answers of some questions and guesses the answers for the remaining questions. Whenever the student knows the answer of a question, he gives the correct answer. Assume that the probability of the student giving the correct answer for a question, given that he has guessed it, is 1 2 . Also ass
Options
- A1 12
- B1 7
- C5 7
- D5 12
Correct answer
C. 5 7
Step-by-step solution
C Correct G Guess K Knows array ll P ( C G )= 1 2 , P ( C K )=1 P ( G C )= 1 6 array aligned & Let required probability = x & P ( G C )= (1- x ) P ( C G ) (1- x ) P ( C G )+ x P ( C K ) & 1 6 = (1- x ) ( 1 2 ) (1- x ) ( 1 2 )+( x )(1) & x = 5 7 Option (3) is correct. aligned