What is the value of a+b+c?

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by Mike@Magoosh » Wed Mar 14, 2012 1:59 pm
Hi, there. I'm happy to help with this. :)

Prompt: What is the value of a+b+c?

Statement #1: (a+b+c)^2=0

The only way you can square something and get zero is if the thing you squared is zero.

(a+b+c)^2=0 --> a+b+c = 0

Statement #1, by itself, is sufficient.

Statement #2: |a|+|b|+|c|=0

The absolute value of any number is greater than or equal to zero. It's greater than zero for any non-zero input, and equal to zero only when the input is zero. Since absolute value can never have a negative output, we know that:

|a|+|b|+|c|=0 --> |a| = 0 AND |b| = 0 AND |c| = 0 ---> a = 0 AND b = 0 AND c = 0

That, in turn, leads to the conclusion that a+b+c = 0. Statement #2, by itself, is sufficient.

Answer = D

Does that make sense? Here's a tricky DS about absolute values.

https://gmat.magoosh.com/questions/964

When you submit your answer choice, the following page has the full video explanation.

Let me know if you have any questions about this.

Mike :-)
Magoosh GMAT Instructor
https://gmat.magoosh.com/