Question

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

{6, 12, 18}
{ }
{3, 6, 9, 12, 15, 18, 24, 30}
{6, 12, 18, 24, 30}

Answer 1

What do you think?

Answer 2

Or to break it down, what are all the members of C and what are all the members of D. In other words, write out C and D explicitly first.

Answer 3

the 3rd one

Answer 4

3rd one is not correct.

Answer 5

oh its the last 1

Answer 6

You're guessing.

What are the members of C?

Answer 7

{integers divisible by 6 from 1 to 30}

Answer 8

This is C explicitly:
C = { 6, 12, 18, 24, 30}

Now, what's D explicitly?

Answer 9

FC Barcelona13: I hope you are not just pasting all your homework here, that way you dont learn anything =). Please try to think about the questions for atleast 5 minutes each before posting. Also it can be helpful to first just ask for tips, not the whole answer. I dont want to sound like nagging, just trying to help you!

Answer 10

{integers divisible by 3 from 1 to 20}

Answer 11

okay i got it

Answer 12

explicitly means that you directly show all the members of the set, not just a description, but a pure list of all the members

Answer 13

its the first one because they are both divisble by 6 and by 3

Answer 14

So what is D explicitly, what are all the members of it?

Answer 15

and they are still between 1 - 30

Answer 16

and they are under 20 also

Answer 17

yes.
For the record, explicitly D is
D = {3,6,9,12,15,18}

Answer 18

Hence if

C = { 6, 12, 18, 24, 30}
and
D = { 3, 6, 9, 12, 15, 18}

then the intersection of C and D
\[ C \cap D = \{ 6, 12, 18 \} \]

Answer 19

Answer is A because it is given in between in both the cases