TS EAMCET 10-Sep-2020 Shift 2 Solved Paper

In an examination there are four Yes/No type of questions. The probability that the answer by the student to a question without guess to be correct is

2

3

. The probability that a student guesses a correct answer is

1

2

. A student writes the examination either by without guessing answers to all the 4 questions or by guessing answers to all 4questions. The probability that he attempt the exam by guessing answers to all questions is

3

7

. Given that a student answered at least 3 questions correctly, the probability that he answered all the questions without guessing is