A typical PIN (personal identification number) is a sequence of any four symbols chosen from the 26 letters in the alphabet and the ten digits. If all PINs are equally likely, what is the probability that a randomly chosen PIN contains a repeated symbol?

Four digit numbers are formed by using the digits 1,2,3,4 and 5 without repeating any digit. Find the probability that a number, chosen at random, is an odd number.

Four digit number are formed by using the digits 1,2,3,4 and 5 wihout repeating any digit.Find the probability that a number chosen at random is an odd number.

From all two-digit numbers with either digit 1, 2, or 3 one number is chosen i) What is the probability of both digits being the same? ii) What is the probability of the sum of the digits being 4 ?

One urn contains two black balls (labelled B1 and B2) and one white ball. A second urn contains one black ball and two white balls (labelled W1 and W2). Suppose the following experiment is performed. One of the two urns is chosen at random. Next a ball is randomly chosen from the urn. Then a second ball is chosen at random from the same urn without replacing the first ball. Write the sample space showing all possible outcomes. What is the probability that two black balls are chosen? What is the probability that two balls of opposite colour are chosen?

One urn contains two black balls (labelled B1 and B2) and one white ball. A second urn contains one black ball and two white balls (labelled W1 and W2). Suppose the following experiment is performed. One of the two urns is chosen at random. Next a ball is randomly chosen from the urn. Then a second ball is chosen at random from the same urn without replacing the first ball. Write the sample space showing all possible outcomes. What is the probability that two black balls are chosen? What is the probability that two balls of opposite colour are chosen?

Three digits are chosen at random from 1,2,3,4,5,6,7,8 and 9 without repeating any digit. What is the probability that the product is odd?

One urn contains two black balls (labelled B_(1) and B_(2) ) and one white ball. A second urn contains one black ball and two white balls (labelled W_(1) , and W_(2) ). Suppose the following experiment is performed. One of the two urns is chosen at random. Next a ball is randomly chosen from the urn. Then a second ball is chosen at random from the same urn without replacing the first ball. (i) Write the sample space showing all possible outcomes (ii) What is the probability that two black balls are chosen ? (iii) What is the probability that two balls of opposite colour are chosen ?

On a normal standard die one of the 21 dots from any one of the six faces is removed at random with each dot equally likely to the chosen.If the die is then rolled,then find the probability that the odd number appears.