Four records are taken out of their jackets, played and returned to the jackets at random. Find the probability that at least one records is put in the right jacket.

Four records are taken out of their jackets, played and returned to the jackets at random. Find the probability that none of the records goes into the right jacket.

Three phonorecords are removed from their jackets, played at random. Find the probability that just one records goes to the right jacket,

Three phonorecords are removed from their jackets, played at random. Find the probability that just two records go to the right jacket,

Three phonorecords are removed from their jackets, played at random. Find the probability that none of the records goes to the right jacket,

Three phonorecords are removed from their jackets, played at random. Find the probability that all three of them go to the right jacket,

A class consists of 25 boys and 15 girls. If a committee of 6 is to be chosen at random, find the probability there is at least one girl in the committee

In bag A, there are 5 white and 8 red balls, in bag B, 7 white and 6 red balls and in bag C, 6 white and 5 red balls. One ball is taken out at random from each bag. Find the probability that all three balls are of the same colour.

A factory has two machines A and B. Past record shows that machine A produced 60% of items of output and machine B produced 40% of items. Further, 2% of items, produced by machine A and 1% produced by machine B were defective. All the items are put into a stockpile and then one item is chosen at random from this and this is found to be defective. What is the probability that it was produced by machine B?

From a box containing 32 bulbs out of which 8 are defective 4 bulbs are drawn at random successively one after anoter with replacement. Find the probability distribution of the number of defective bulds.