Tricks To Solve Probability Questions Last Updated : 22 Nov, 2024 Comments Improve Suggest changes Like Article Like Report The application of probability can be seen in quantitative aptitude as well as in daily life. It is essential to understand the basic concepts of probability to solve the problems efficiently. This article will cover the foundational concepts of probability and provide techniques to solve problems of varying difficulty levels, helping students preparing for competitive exams such as SBI PO, SBI CLERK, IBPS PO, IBPS CLERK, RRB PO, NICL AO, LIC AAO, SNAP, MAT, SSC CGL, and more. Tips and Tricks for ProbabilityWhen solving probability problems, if it's easier to calculate the probability of an event not occurring, subtract that probability from 1 to find the likelihood of the event happening. For example, P(E’) = 1 – P(E).If the term "or" appears in a question, use addition (+) when applying the Fundamental Principle of Counting.If the term "and" appears in a question, use multiplication (×) when applying the Fundamental Principle of Counting.Number of Outcomes for Rolling Dice = 6n, where n is the number of dice rolled at once:For 1 die, the outcomes are 61 = 6.For 2 dice, the outcomes are 62 = 36.For 3 dice, the outcomes are 63 = 216.Number of Outcomes for Tossing Coins = 2n, where n is the number of coins tossed at once:For 1 coin, the outcomes are 21 = 2.For 2 coins, the outcomes are 22 = 4.For 3 coins, the outcomes are 23 = 8.Number of Outcomes for Drawing a Card = 52n, where n is the number of sets or decks of cards used:For 1 deck of cards, the outcomes are 521 = 52.For 2 decks of cards, the outcomes are 522 = 2,704.For 3 decks of cards, the outcomes are 523 = 140,6085.The sum of the probability of an event and its complement is 1, i.e., P(A) + P(A′) = 1.The probability of an impossible event or an event not happening is always 0, i.e., P(∅) = 0.The probability of a sure event is always 1, i.e., P(A) = 1.The probability of any event lies between 0 and 1, i.e., 0 < P(A) < 1.The formula for the union of two events A and B: P(A∪B) = P(A) + P(B) − P(A∩B).For mutually exclusive events A and B: P(A∪B) = P(A) + P(B).Additional Formulas:Probability of Union of Two Events: P(A∪B) = P(A) + P(B) − P(A∩B).Probability of Complement of an Event: P(A′) = 1 − P(A).Conditional Probability: P(A∣B) = P(B)P(A∩B).Probability of Intersection of Two Events: P(A∩B) = P(A) × P(B∣A).Use Venn Diagrams: For problems involving intersections or unions of events (like "either A or B happens"), a Venn diagram can help visualize the problem and ensure that you're not double-counting or overlooking possibilities.When a coin is tossed n times or n coins are tossed once, the probability of each specific outcome is 1/2n.When a die is rolled n times or n dice are rolled simultaneously, the probability of any specific outcome is 1/6n.If n cards are drawn from a deck without replacement, the number of possible outcomes is determined by combinations. The probability of each specific event is given by:P (E) = 1/C(52, n) If n cards are drawn one after the other with replacement, each draw is independent and the number of possible outcomes for each draw remains 52. Therefore, the probability of each simple event is given by:P(E) = 1/52n.Note: A probability of 1 means an event will definitely occur, while 0 means it will definitely not occur.Articles related to Probability:Probability in Maths.Probability Formulas.Probability Aptitude Questions and Answers.Quiz on Probability. Comment More infoAdvertise with us A ansarisahin432 Follow Improve Article Tags : SSC/Banking SSC Quantitative Aptitude Banking Quantitative Aptitude SSC Practice Paper Banking Practice Paper +1 More Similar Reads SBI PO Computer Practice QuestionsSBI PO Reasoning Practice QuestionsAlphanumeric Series - Logical Reasoning Questions and AnswerAlphanumeric series is formed by combining both alphabets and numbers. 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