Question

If C = {integers divisible by 6 from 1 to 30} and D = {integers divisible by 3 from 1 to 20}, what is C ∩ D?

Answer 1

lists of what?

Answer 2

C ∩ D means C intersect D

in other words its the set of elements which are members of both C and D.

Answer 3

the easiest way to do this is to list all the elements in C and D

Answer 4

C = {6, 12, 18, 24, 30}

now list D

and compare with C