If out of 20 consecutive whole numbers two are chosen at random, then find the probability that their sum is odd.

Out of 3n consecutive integers, there are selected at random. Find the probability that their sum is divisible by 3.

Two integers are chosen at random and multiplied. Find the probability that the product is an even integer.

A box contains 6 nails and 10 nuts. Half of the nails and half of the nuts are rusted. If one item is chosen at random, then find the probability that it is rusted or is a nail.

If four whole numbers taken art random are multiplied together, then find the probability that the last digit in the product is 1,3,7, or 9.

Two squares are chosen at random on a chessboard, the probability that they have a side in common is:

An integer is chosen at random and squared. Find the probability that the last digit of the square is 1 or 5.

Suppose that 5 males out of 100 and 25 females out of l000 are colour blind. A colour blind person is chosen at random. What is the probability that a male is chosen (assume that the number of males and females are equal)?

A bag contains 50 bolts and 150 nuts. Half of the bolts and half of the nuts are rusted. If an item is chosen at random, find the probability that it is rusted or that it is a bolt.