Mark the correct alternative in each of the following:

A person writes 4 letters and addresses 4 envelopes. If the letters are placed in the envelopes at random, then the probability that all letters are not placed in the right envelopes, is

Mark the correct alternative in each of the following:

Three faces of an ordinary dice are yellow, two faces are red and one face is blue. The dice is rolled 3 times. The probability that yellow red and blue face appear in the first second and third throws respectively, is

Mark the correct alternative in each of the following:

The probability that a leap year will have 53 Friday 53 Saturdays is

Mark the correct alternative in each of the following:

A speaks truth in 75% cases and B speaks truth in 80% cases. Probability that they contradict each other in a statement, is

Mark the correct alternative in each of the following:

Three integers are chosen at random from the first 20 integers. The probability that their product is even is