My good friends!, I trust you are all well and alive!!..The problem I'm going to give, I'll describe in maybe more detail than is necessary, but I need to make sure that nothing is mis-understood. They give the following:

126 Grade 11 learners, 44 of them take Math, 112 take History and 90 take Science. All the learners who take Math, also take History. 80 Learners take both History and Science and 30 take both Math and Science.

Show this information on a Venn diagram.

I tried to upload an image, but could not. So I will explain my best. Since they do not give the intersect value for all 3 subjects, we have to calculate that, I presume...using the reference 'x", and subsequently all intersections will have values with respect to "x".

I calculated "x" to be 34..the inmost centre part..they have it as 30, with 4 being completely excluded..I do not get that..

Maths only ends up a zero,- I get that

History only ends up 18 - also fine

Science only ends up 10 - fine

Science and History = 50..???

All three subjects = 30...???

Excluded =4...????

Please help me with this?...Thank you all very very much!!

juriemagic Sep 9, 2019

#1**0 **

my answer got wiped ;-; I have no idea why (or am i just dum dum)

But, I think you were right. My answers came out the same as yours.

Guest Sep 10, 2019

#3**0 **

Just a question on this as well....if they do not give the centre value, do we accept always that that value should be calculated by using the "x" method..or should we accept that it is zero then....and omit it?...

juriemagic Sep 10, 2019

#4**+2 **

**126 Grade 11 learners, 44 of them take Math, 112 take History and 90 take Science. **

**All the learners who take Math, also take History. **

**80 Learners take both History and Science and **

**30 take both Math and Science.**

I assume:

heureka Sep 10, 2019

#5**0 **

Hello Heureka,

yes, this is as they have it also, so I believe this is right...what I struggled with is the centre 30. If you calculated x, it comes out to be 34 and not 30. The equation for maths ends up being x-30. So saying then 34-30, we get 4, which should be math only...however we know that ALL math also take History, so what to do with the 4 then?....cast it outside?...

I do firmly understand the outcome, was just concerned about the fact that x calculated to 34 and not 30, in which case math only would have calculated to 30-30 which is zero...

thank you for helping out to understand this approach..

juriemagic
Sep 10, 2019