help on a math question

[QueenieReighn]

So we are having a debate here and would love some help.  Here is the math problem:  Rena had some Brazil and Canada stamps.  4/7 of the stamps were Brazil stamps and the rest were Canada stamps.  She gave away 1/12 of the Canada stamps to her best friend.  What fraction of the Canada stamps did she have left?  The book says the answer is 27/28 and one person here came up with the answer being 11/28 and the other with 11/12.  A little help to end the debate please!

[kiana]

The problem is written wrong, it should be some variation "What fraction of her stamps did she have left?"

 

3/7 of the stamps were Canada stamps, and she gave away 1/12 of those, so she gave away (3/7)(1/12) = 1/28 of her stamps. She has 27/28 of her stamps left. 

 

11/12 is correct as written. If she gave away 1/12 of her Canada stamps, she would have 11/12 of her Canada stamps left. 

[Kiara.I]

If the book says what fraction of the Canadian stamps are left, it should be 11/12.

 

But if the book says what fraction of stamps are left, total, it should be 27/28.

 

And if the book says what fraction of the stamps that are left are Canadian, it should be 11/28.

 

Sent from my Nexus 5 using Tapatalk

[QueenieReighn]

Thank you!  I kept thinking this question is written wrong, but figured I was missing something.

[forty-two]

So we are having a debate here and would love some help. Here is the math problem: Rena had some Brazil and Canada stamps. 4/7 of the stamps were Brazil stamps and the rest were Canada stamps. She gave away 1/12 of the Canada stamps to her best friend. What fraction of the Canada stamps did she have left? The book says the answer is 27/28 and one person here came up with the answer being 11/28 and the other with 11/12. A little help to end the debate please!

The question is confusingly worded imo. Given the book's answer, I think they mean to ask "what fraction of the *stamps* were left," not "what fraction of the Canada stamps were left". Wrt the question as written, I agree with the 11/12 answer - if you give away 1/12 of your Canada stamps, then you have 11/12 of your Canada stamps remaining. But that's trivial and probably not what they meant to ask.

 

If you try to answer what I'm thinking they *meant* to ask, given the answer key, then here's how I'd do it:

The canada stamps are 3/7 of the whole.

1/12 of the canada stamps are given away, which is (1/12)*(3/7) = 1/28 of the whole.

So there are 1-(1/28) stamps remaining, which is 27/28.

 

Does that make sense?