a bag of nuts - fractions

[vend]

I've had this question twice now on my gre - it involves an 8 lb bag of nuts where a certain fraction of total nuts are walnuts, then, 3 more pounds of walnuts are added - what is the total of walnuts in the bag as a a fraction - has anyone seen this? There is likely some detail I am missing. But it stumps me. Help?

[tommywallach]

Hey Vend,

So obviously you haven't printed quite enough for me to get an idea, but I'll try making up a question here on the spot that simulates what you're saying:

I've got a twelve bag bag of jellybeans where 3/8 of the jellybeans are blue. If I add 3 more pounds of blue jellybeans, what is the fraction of the bag that is now blue jellybeans?

To solve this question, you'd start by solving for the amount of jellybeans in the original bag.

3/8 * 12 = 36/8 = 4.5 pounds of blue jellybeans

Now you're adding 3 pounds more of blue jellybeans, but be careful! You're also adding 3 pounds to the total (i.e. this is now a 15 pound bag of jellybeans).

4.5 + 3 = 7.5 pounds of blue jellybeans
12 + 3 = 15 pounds of jellybeans in total

7.5/15 = 1/2 = the new ratio of blue jellybeans to total jellybeans

Let me know if that adequately simulated your question!

-t