Maths · Class 11 · Chapter 14
Probability
11 lessons 93 min 2 simulations
Probability turns 'how likely' into a number. The chapter treats every event as a subset of a sample space, names the impossible, sure, simple and compound events, and combines events with complement, union, intersection and difference. It then sets out the three axioms any assignment of probabilities must satisfy, finds P(A) by adding outcome probabilities, specialises to equally likely outcomes where P(E) = n(E)/n(S), and proves the addition rule, which removes the overlap A ∩ B counted twice, and the complement rule P(not A) = 1 − P(A), using counting for larger sample spaces.
What the exam asks
Probability is a regular JEE Main topic, and this chapter's rules carry the later Class XII chapter on conditional probability. Questions test writing the right sample space, deciding whether events are mutually exclusive or exhaustive, checking whether an assignment of probabilities is valid, the addition rule for two and three events, the complement rule for 'at least one', and card, dice and selection problems solved with combinations. Marks are lost by using unequal outcomes as if equally likely, by adding P(A) and P(B) without removing the overlap, and by miscounting ordered versus unordered selections.
Lessons
11 lessons · 93 min
1Events and sample spacesNCERT §14.17 min2Occurrence and types of eventsNCERT §14.1.1, §14.1.27 min3Algebra of eventsNCERT §14.1.37 min4Mutually exclusive and exhaustive eventsNCERT §14.1.4, §14.1.57 min5Axioms of probabilityNCERT §14.27 min6Probability of an eventNCERT §14.2.110 min 1 sim7Equally likely outcomesNCERT §14.2.27 min8Probability of A or BNCERT §14.2.311 min 1 sim9Probability of not ANCERT §14.2.47 min10Probability by countingNCERT §14.2.4, Examples 8 to 128 min11Chapter reviewMust-know facts, traps and formulas15 min