1)

An urn contains 9 blue, 7 white and 4 black balls. If 2 balls are drawn at random, then what is the probability that only one ball is white?

2)

What is the probability that a card drawn at random from a pack of 52 cards is either a King or a Spade?

3)

In an urn there are 4 red balls and 3 blue balls. if two balls are drawn at random, find the probability that none is red.

4)

An urn contains 9 blue, 5 white and 7 black balls. If 2 balls are drawn at random, what is the probability that only one ball is white?