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## Comment on

Avoiding Common Mistakes - Part I## Thank you. That was really

## Just to clarify, for don't

By that logic 4.25x-11.75=14.75 should be sufficient? If not, how do you evaluate sufficiency without calculating?

## The target question asks

The target question asks "Does x = 6?"

IF we were to solve the equation, 4.25x - 11.75 = 14.75, we'd get ONE solution. At that point, we'd be able to definitively answer the target question.

Since we COULD answer the target question with certainty, that statement is sufficient.

All we need to know here is that the equation 4.25x - 11.75 = 14.75 will yield exactly one solution. Given this, we don't have to solve the equation for x.

Does that help?

Cheers,

Brent

## Ohhhhhhhhh, I got it now.

## Exactly!

Exactly!

## thanks

## Hi Brent, just on

## If the target question asks

If the target question asks "Does x = 6?" and statement 1 says "x + 1 = 4", then statement 1 would still be sufficient, because we can still answer the target question with absolute certainty.

That is, I can provide an definitive answer to the target question: NO, x definitely does NOT equal 6.

You're not alone. Many students compare the answer to the target question with the answer to the sufficiency question. This is covered starting at 3:28 in the above video.

Cheers,

Brent

## Great explanation, got that!

## Exactly!

Exactly!

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