Sets Exemplar — Class 11 Mathematics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 11 Mathematics chapter "Sets Exemplar" — 5 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 11 Mathematics chapter "Sets Exemplar" — 5 important questions with detailed answers for CBSE board exam p…
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NCERT Solutions for Class 11 Mathematics — Sets Exemplar. Step-by-step answers to all 5 textbook questions from this chapter, written for CBSE board preparation and free to use.
Sets Exemplar — All 5 Questions Solved
Q1. If A = {1, 2, 3, 4} and B = {3, 4, 5, 6}, find A ∩ B and A ∪ B.
A ∩ B = {3, 4} (common elements). A ∪ B = {1, 2, 3, 4, 5, 6} (all elements).
Q2. If U = {1, 2, 3, 4, 5, 6} is universal set and A = {1, 3, 5}, find A'.
A' (complement) = U - A = {2, 4, 6}.
Q3. Verify De Morgan's law: (A ∪ B)' = A' ∩ B' using A = {1, 2}, B = {2, 3}, U = {1, 2, 3, 4}.
A ∪ B = {1, 2, 3}. (A ∪ B)' = {4}. A' = {3, 4}, B' = {1, 4}. A' ∩ B' = {4}. LHS = RHS. Verified.
Q4. If n(A) = 30, n(B) = 40, n(A ∩ B) = 10, find n(A ∪ B).
n(A ∪ B) = n(A) + n(B) - n(A ∩ B) = 30 + 40 - 10 = 60.
Q5. In a survey, 50 students like tea, 60 like coffee, 20 like both. How many like at least one?
Using inclusion-exclusion: n(Tea ∪ Coffee) = 50 + 60 - 20 = 90 students.
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.