billyr wrote:Why statement 1 alone suff?

i thought statement 1 is insuff since the symbol can be addition or multiplication?

Thanks

The good news is that you're right. The bad news is that you're also wrong!

You're 100% correct that, based on statement (1), we can't determine if the operation is addition or multiplication.

However, you're not answering the correct question. In Data Sufficiency, we have to make sure our focus is in the right place.

The question is NOT: "which of the 4 operations does the triangle represent?" The question is: "is the equation listed true?"

Since that equation holds true for BOTH addition and multiplication, statement (1) gives us a definite "YES" answer to the question: sufficient.

Statement (2), on the other hand, holds true for addition and subtraction. The original equation holds true for addition, but NOT for subtraction, so (2) can give us both a "YES" and a "NO" answer: insufficient.

(1) is sufficient alone, (2) isn't: choose (A).

(1) In order for this to be correct, the symbol can be either + or * (addition of multiplication).

However, we're not asked whether we can determine exactly what the symbol means. We're asked if the statement is true.

Plugging in + for the symbol works.
Plugging in * for the symbol works.

So, even though the symbol could be two different things, they both result in the same true answer to the question. So (1) is sufficient.

(2) Could be either + or - (addition or subtration).
When we plug them in...

Plugging in + for the symbol works.
Plugging in - for the symbol does not work.

These answers conflict. So (2) is insufficient.

Answer A.

billyr wrote:Why statement 1 alone suff?

i thought statement 1 is insuff since the symbol can be addition or multiplication?

Thanks

Same here... Any explanations.. I tried substituting too, but just cant figure it out!!!

Thanks stuart/billy!!!
Oh my god i think i need some serious practice!!!!! This is the second time today %@#$%@$%