Question

If A={x:x is multiple of 3}
B={x:x is multiple of 5} then A-B is?

a) A intersection B

b)A intersection B dash

c) A dash intersection B dash

Answer 1

A=(3 6 9 12 15 18 21 24 27 30)

B=(5 10 15 20 25 30 35 40 45 50)

A-B= ( 15 ,30)

Answer 2

Answer:

b) A ∩ B'

Step-by-step explanation:

A= {x : x is multiple of 3},

⇒ A= {3, 6, 9, 12, 15.....}

B = {x : x is multiple of 5},

⇒ B = { 5, 10, 15, 45, 60,....}

A - B = elements of A which are not on B

= { 3, 6, 9, 12, 18, .....}

A ∩ B = { 15, 45, 60, 75, ....}

A ∩ B' = common element of the set A and the elements which are not in B,

= { 3, 6, 9, 12, 18, ....},

A' ∩ B' = common element of the elements which are not in set A and the elements which are not in B,

≠ A - B ,

Hence, OPTION b) is correct.