What is the probability of guessing correctly at least 8 out of 10 answer on true-false examination?

Ten coins are tossed. The probability of getting at least 8 heads is

The probability that a student will pass the final examination in both English and Tamil is 0.5 and the probability of passing neither is 0.1 . If the probability of passing the English examination is 0.75, what is the probability of passing the Tamil examination ?

The probability that a student will pass the final examinatin in both English and Hindi is 0.5 and the probability of pasing neither is 0.1. If the probability of passing the English examination is 0.75. What is the probability of passing the Hindi examination?

The probability of guessing the correct answer to a certain question is (x)/(3) . If the probability of not guessing the correct answer is (x)/(5) , then find the value of x .

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 student knows the answer given that he answered it 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 student knows the answer given that he answer it correctly?