Q2 of 71 Page 23

If A = {x : x is a multiple of 5, x ≤ 30 and }

B = {1, 3, 7, 10, 12, 15, 18, 25},


Find (i) A ∪ B (ii) A ∩ B

A = {x : x is a multiple of 5, x ≤ 30 and x ∈}


A contains the natural numbers that are less than or equal to 30 and multiples of 5.


∴ A = {5, 10, 15, 20, 25, 30}


B = {1, 3, 7, 10, 12, 15, 18, 25}


∴ A ∪ B = {1, 3, 5, 7, 10, 12, 15, 18, 20, 25, 30} [elements that are present in either A or B]


∴ A ∩ B = {10, 15, 25} [elements that are present in both A and B]


More from this chapter

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20

Let

A = {x : x is a natural number < 11}


B = {x : x is an even number and 1 < x < 21}


C = {x : x is an integer and 15 ≤ x ≤ 25}


i. List the element of A, B, C


ii. Find n(A), n(B), n(C)


iii. State whether the following are True (T) or False (F)


a)


b)


c)


d)

1

Find A ∪ B and A ∩ B for the following sets.

i. A = {0, 1, 2, 4, 6} and B = {−3, −1, 0, 2, 4, 5}


ii. A = {2, 4, 6, 8} and B = Φ


iii. and B = {x : x is a prime number less than 11}


iv. and

3

If X = {x : x = 2n, x ≤ 20 and } and Y = {x : x = 4n, x ≤ 20 and }

Find (i) X ∪ Y (ii) X ∩ Y

 4

U = {1, 2, 3, 6, 7, 12, 17, 21, 35, 52, 56},

P = {numbers divisible by 7}, Q = {prime numbers}


List the elements of the set {x : x ∈ P ∩ Q}