Two cards are drawn at random and without replacement from a pack of 52 playing cards. Find the probability that both the cards are black.

A die is tossed thrice. find the probability of getting an odd number atleast once?

The ratio of the number of boys to the number of girls in a class is 1:2. It is known that the probability of a girl and a boy getting a first class are 0.25 and 0.28 respectively. Find the probability that a student chosen  at random will get first class?

An integers is chosen at random from the first fifty positive integers. What is probability that the integer chosen is a prime or multiple of 4.

Two cards are drawn one by one at random from a deck of 52 playing cards. What is the probability of getting two jacks if
(i) the first card is replaced before the second card is drawn
(ii) the first card is not replaced before the second card is draw?