Question

Discrete math/sets: Out of a group of 191 students, 10 are taking French, business, and music; 36 are taking French and business; 20 are taking French and music; 18 are taking business and music; 65 are taking French; 76 are taking business; and 63 are taking music.

1. How many are taking French and music but not business?
2. How many are taking business and neither French nor music?
3. How many are taking French or business (or both)?
4. How many are taking music or French (or both) but not business?
5. How many are taking none of the three subjects?

Answer 1

apply set formulas...this may help
http://grockit.com/blog/gmat/2011/01/28/formulas-for-set-theory/

Answer 2

Hi, I think you could try Venn diagrams for this question. Have you heard of these before, or would you like me to explain?

Answer 3

yeah yeah sure still don't quite see the math though.

1. (F intersect M = 20) - B = 10? How do you even write that?
Then for #2 76 are taking business, 36 w/ french and 18 w/ music; so I just subtract them to get 22 as the answer? So B - (F union M) = 22 is that how you write it?

Answer 4

Or is F union M not 54

Answer 5

44 then..?

Answer 6

so B - (F union M) = 32 am i close

Answer 7

And Q#5 throws me off, is that a trick question then? That's why I thought 191 = the universe rather than just the union of all subject-sets. So is the answer to #5 then the null set and 191 is the union of the three sets?

Answer 8

Can I say something?

Answer 9

yeah please

Answer 10

your Veen is not correct

Answer 11

then, 36 taking F and B