Question: Nut Mix

Comment on Nut Mix

Brent, If i wrote the following: 0.09X+ 0.24W = 0.15(X+W) - just looking at the sum of cashews and the combined result and got to the same equation as you did. was i wrong to do so? Because i did not use fraction and something feels off..
gmat-admin's picture

Your approach is totally valid.

I expressed 15% as 15/100, and you expressed it as 0.15. Both are valid.

Brent,

I solved in a different way, here below my answer:
24w + 9x = 15y
w + x = y

So, I have a system and if I know w or y, I can find x. Then:
1) Sufficient
2) Sufficient

Is it a valid approach?

Thanks,
Pedro
gmat-admin's picture

Perfectly valid - nice work!

Hi Brent,

When you were solving for statement 1, why did you suggest to use 2 equations to solve for X when we could have just substituted the value of W in 9W - 6X = 0 to get the value of X ?
gmat-admin's picture

I believe you're referring to what happens at 2:07 in the above video.

You're absolutely right to say that we COULD replace w with 30 in order to determine the value of x (but we'd never waste our time on test day doing so).

For Data Sufficiency questions, our sole goal is to determine whether we have sufficient information to answer the target question.
So, once we know that 9w - 6x = 0 and w = 30, we don't really need to solve the equation for x.
We need only recognize that we COULD replace w with 30 in order to determine the value of x.

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