Venn Diagram

Deep · 11 Oct 2012 at 22:49

Hi All,

I've just had a phone call from my aunt and she's having trouble with my cousins homework.

I cannot figure it out

Damn GCSE's

If a total of 40 people have seen Harry Potter on either DVD, Cinema, Video or a combination of them.

Video 23
DVD 22
Cinema 17
Video and DVD 12
Video and Cinema 6
DVD and Cinema 7

How many people have watched Harry Potter on all Video, DVD and Cinema?

The answer is probably obvious but I cannot figure it out at all!

So if anyone knows, please let me know!

OpenToSuggestions · 11 Oct 2012 at 22:59

I think the answer is three.
I haven't done Venn diagrams for many ears and that is purely an educated guess.

EDIT: Scrap that I have even less of an idea than I thought!

King Damager · 11 Oct 2012 at 23:16

If this is still unsolved by midday tomorrow I'll do it for you. Don't have time right now though.

kd

RetiredGreyFox · 11 Oct 2012 at 23:34

Forget it

minister · 11 Oct 2012 at 23:46

Deep said:
Hi All,

I've just had a phone call from my aunt and she's having trouble with my cousins homework.

I cannot figure it out Damn GCSE's

If a total of 40 people have seen Harry Potter on either DVD, Cinema, Video or a combination of them.

Video 23
DVD 22
Cinema 17
Video and DVD 12
Video and Cinema 6
DVD and Cinema 7

How many people have watched Harry Potter on all Video, DVD and Cinema?

The answer is probably obvious but I cannot figure it out at all!

So if anyone knows, please let me know!

3, you need to know how many arent any of the 3

Pawnless Endgame · 11 Oct 2012 at 23:59

GCSEs are supposed to be educating students. I see videos and DVDs as miseducation as they are both videos essentially. The question on the paper should have listed VHS and DVD as the first 2 :-)

Same debate as "is it a PC or a laptop?"

Fenris · 12 Oct 2012 at 00:01

Pretty sure it's 3.

It becomes fairly obvious if you actually draw the diagram.

Dist · 12 Oct 2012 at 00:07

Monserrat said:
GCSEs are supposed to be educating students. I see videos and DVDs as miseducation as they are both videos essentially. The question on the paper should have listed VHS and DVD as the first 2

Same debate as "is it a PC or a laptop?"

Would kids around GCSE age know what VHS is?

Zbornak · 12 Oct 2012 at 00:10

A remember a teacher mentioning Venn diagrams at school, several times. Meh.

One · 12 Oct 2012 at 00:10

One · 12 Oct 2012 at 00:11

Dist said:
Would kids around GCSE age know what VHS is?

What is being implied by video, if not VHS?

mufc802 · 12 Oct 2012 at 00:12

Use algebra to work it out. Say the value for all three is x. Draw the diagram and work backwards. So if Video and DVD is 12, do "12 - x", etc.

40 = x + 12 – x + 6 – x + 7 – x + 23 – (12-x) – x – (6-x) + 22 – (12-x) –x –(7-x) + 17 – (6-x) – x –(7-x)

40 = x + 37

x=3

Nitefly · 12 Oct 2012 at 00:19

I'm probably being a right tard chops, but in that diagram how do you know how many are exclusively in video?

23-12-6=5 sure, but isn't that 5 to be split between 'just video' and 'all 3'? Think I'm reading the question wrong.

One · 12 Oct 2012 at 00:26

Nitefly said:
I'm probably being a right tard chops, but in that diagram how do you know how many are exclusively in video?

23-12-6=5 sure, but isn't that 5 to be split between 'just video' and 'all 3'? Think I'm reading the question wrong.

I didn't say it was right...

Nitefly · 12 Oct 2012 at 00:31

desires said:
I didn't say it was right...

Haha, nice edit

You have 26 for video in your pic, but the question says 23.

n3mss · 12 Oct 2012 at 00:33

desires said:
I didn't say it was right...

I think you are right. But, more importantly, why aren't the circles and intersections different colours?

One · 12 Oct 2012 at 00:38

Thinking about it for more than one minute I now think the question is impossible to answer. You need to solve the set equations:

V = 5 + x;
D = 3 + x;
C = 4 + x;

There can be multiple answers seeing as we only really fully know the intermediate steps.

What's confusing the problem is that the core options (V, D, C) have been compounded and we don't know if the compound includes the 'all (x)' option or not. I'm going to use some experience though and assume it's not this complicated as it's GCSEs and therefore my initial picture is the correct answer.

Nitefly · 12 Oct 2012 at 00:40

desires said:
Thinking about it for more than one minute I now think the question is impossible to answer. You need to solve the set equations:

V = 5 + x;
D = 3 + x;
C = 4 + x;

There can be multiple answers seeing as we only really fully know the intermediate steps.

That's what I immediately thought. I just didn't want to look really stupid

I always reserve the right to look that way though

One · 12 Oct 2012 at 00:45

Nitefly said:
That's what I immediately thought. I just didn't want to look really stupid

I always reserve the right to look that way though

You can probably make it even more complicated by questioning whether the intermediate steps are also compounds of the 'all' option. Because of all this nonsense I am convinced my picture is correct. Occam's' razor and whatnot.

n3mss · 12 Oct 2012 at 00:47

desires said:
You can probably make it even more complicated by questioning whether the intermediate steps are also compounds of the 'all' option. Because of all this nonsense I am convinced my picture is correct. Occam's' razor and whatnot.

I take it from this comment that this is why there is a lack of colours in your diagram. Personally I would have chosen red, green and blue for the main circles and the RGB combination for the intersections.