Find the probability of guessing correctly at least seven out of ten answersin a 'true' or 'false' objective test.

The probability of guessing correctly at least six of 10 answers in True or False objective test is

Two dice are thrown . Find the probability of the following events The sum of the numbers on their upper faces is at least 9.

Find out correctly matched pair

If two dice are rolled simultaneously, find the probability of the following events : The sum of the digits on the upper faces is at least 10.

The probability that a student knows the correct answer to a multiple choice question is 2/3 . If the student does not know the answer, then the student guesses the answer. The probability of the guessed answer being correct is 1/4 . Given that the student has answered the question correctly the probability that the student knows the correct answer is

In an entrance test, there are multiple choice questions. There are four possible answers to each question, of which one is correct. The probability that a student knows the answer to a question is 90%. If he gets the correct answer to a question, then find the probability that he was guessing.

Find the odd man out: (i) Force responsible for a string to become tout on stretching Weight of an object The force due to which we can hold an object in hand.