In an examination 20 question of true false type are asked suppose a student tosses a fair coin to determine his answer to each question if the coins falls heads he answers true if it falls tail he answers false find the probability thet he answers at least 12 question correctly.

In answering a question on a multiple choice test,a student either knows the answer or guesses. Let 3/4 be the probability that he knows the answer and 1/4 be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability 1/4. What is the probability that the studdent knows the answer given that he answered it correctly?

To a question, a student answered that bakelite is the thermosetting polymer. IS he answer correct?

In an examination a question paper consists of' 12 questions divided into 2 parts I and H containing 5 and 7 questions respectively. A student is required to attempt 8 questions. In how many ways the student can answer 8 questions by selecting at least 3 questions from each part.

A student is Instructed to answer any 8 out of 12 questions. How many different ways he can choose the questions?

A student is to answer 10 out of 13 questions in an examinations such that he must choose at least 4 from the first five questions . The number of choices available to him is :

A student is Instructed to answer any 8 out of 12 questions. How many different ways he can choose the questions so that question no.1 will be included?

A student is Instructed to answer any 8 out of 12 questions. How many different ways, he can choose the questions so that question no.1 will be included and question no.10 will be excluded?