# Important Questions for Class 11 Chapter 1 - Sets

We have come up with the Class 11 Important questions with step-by-step solutions by experienced academicians to get over that difficult problem or understanding a tough concept. You can download our free math Important questions, now for even preparing for final exams.

**Important questions based on NCERT syllabus Chapter 1 - Sets:**

*Question 1*: Let A = { x: 6-x =0} and B = x: x is a root of the equation x^2 - 5x + 6 = 0}, Is A and B are equal?

Solution:

Consider x^2 - 5x + 6 = 0

Find the root of the equation.

x^2 - 3x - 2x + 6 = 0

x(x-3)- 2(x-3) = 0

(x-3)(x-2) = 0

x = 3 0r x = 2

A = 6 - 3 = 3 and 6 - 2 = 4

For one root the sets are equal(A = B)

*Question 2*: Identity the following whether the given set are disjoint set or not

i) A = { 2,4,6,8} and B = {3,4,6,9}

ii) P = {1, 0, 9, 7} and Q = {2, 5, 8, 2}

*Solution*:

i) Two sets are said to be disjoint if they have no element in common. i.e., A ∩ B = ϕ

A ∩ B = { 2,4,6,8} ∩ {3,4,6,9} = { 4, 6} ≠ ϕ

Hence A and B are not disjoint set.

ii) P ∩ Q = {1, 0, 9, 7} ∩ {2, 5, 8, 2} = {ϕ}

Hence P and Q are disjoint set.

*Question 3*: if A = { 1,2, 3,4} and B = {3, 4, 6, 8}. Find A - B and B - A

*Solution*:

A - B = { 1,2, 3,4} - {3, 4, 6, 8} = {1,2,3}

B - A = {3, 4, 6, 8} - { 1,2, 3,4} = {3,6,8}

*Question 4*: Let P = { a,b,b,v,x,d} and Q = { q,d,f,g, h}. Find P U Q and P ∩ Q

*Solution*:

P U Q = { a,b,b,v,x,d} U { q,d,f,g, h} = {a,b,v,x,d,q,f,g,h}

P ∩ Q = { a,b,b,v,x,d} ∩ { q,d,f,g, h} = {d}