Word Problems - Chapter 7 (probability) - Question 6

[cristina.boquin]

Hi! On question 6 from Problem Set in Chapter 7 (word problems guide), I'm confused about the answer -if half of the 12 guests are men, and the other half are women,and 1 man and 1 woman are bringing a dessert I thought that would mean 10 out of 12 guests (either man or woman) would not be bringing a dessert...the answer however is 11/12. Could you please clarify further? The explanation in the guide is not particularly helpful. Thanks!

[tommywallach]

Hello Cristina! How goes?

Looks like you misunderstood the question.

You thought it asked this: What are the odds that it's a woman or a man who didn't bring dessert?

But it asked: What are the odds that it's a woman, OR a man who didn't bring dessert.

There's a 6/12 chance that it's a woman.

Then, there's a 5/12 chance that it's a man who didn't bring dessert.

In short, we are still allowed to count the woman who DID bring dessert, because we only cared about the MAN who didn't bring dessert.

Make sense?

-t

P.S. In the future, please title your post with the book name, chapter name, and question number, so other people can tell what the thread is about. I've changed this one for ya. : )

[cristina.boquin]

Ahhh that makes total sense, tricky way to word the question... thanks so much!

P.S. Will definitely follow proper forum-post-etiquette next time!

[tommywallach]

No problem! : )

-t