Probability Aptitude Mastery
Advanced Quantitative Scenarios for Competitive Excellence
📊 Probability – Concept & Formulas
💡 What is Probability?
Probability is the measure of the likelihood that an event will occur. It always ranges between 0 (Impossible) and 1 (Certain).
P(E) = Number of Favorable Outcomes / Total Number of Outcomes
- Sample Space (S): The set of all possible outcomes.
- Event (E): A subset of the sample space.
⚡ Exam Quick Reference
Memorize these total outcomes (Sample Spaces) for faster solving:
1 Coin2 Outcomes
2 Coins2² = 4 Outcomes
3 Coins2³ = 8 Outcomes
1 Die6 Outcomes
2 Dice6² = 36 Outcomes
Playing Cards52 Total Cards
📝 Essential Formulas
Complementary Event: Probability of an event NOT happening.
P(Not E) = 1 - P(E)
Addition Rule (OR): Probability of A or B occurring.
P(A ∪ B) = P(A) + P(B) - P(A ∩ B)
Multiplication Rule (AND): For independent events.
P(A ∩ B) = P(A) × P(B)
Guru Guidance: In competitive exams, always look for the word "At least"—it's a signal to use the Complementary Formula (1 - None) to save time!
