Is p + pz = p?

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Is p + pz = p?

by BTGmoderatorDC » Tue Sep 11, 2018 8:34 pm

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Is p + pz = p?

(1) p = 0

(2) z = 0

OA D

Source: GMAT Prep

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by Jay@ManhattanReview » Wed Sep 12, 2018 3:12 am

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BTGmoderatorDC wrote:Is p + pz = p?

(1) p = 0

(2) z = 0

OA D

Source: GMAT Prep
Let's take each statement one by one.

(1) p = 0

We have p + pz = p; at p = 0, we have 0 + 0*z = 0 => 0 = 0. Sufficient. Irrespective of the value of z, at p = 0, p + pz = p.

(2) z = 0

We have p + pz = p; z = 0, we have p + p*0 = p => p = p. Sufficient. Irrespective of the value of p, at z = 0, p + pz = p.

The correct answer: D

Hope this helps!

-Jay
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by Brent@GMATPrepNow » Wed Sep 12, 2018 6:01 am

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BTGmoderatorDC wrote:Is p + pz = p?

(1) p = 0

(2) z = 0

Target question: Is p + pz = p?
This is a great candidate for rephrasing the target question.
Aside: Here's a video with tips on rephrasing the target question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1100

Take Is p + pz = p? and subtract p from both sides to get: Is pz = 0?

In order for pz to equal 0, it must be the case that either p = 0 or z = 0 (or they both equal 0)

REPHRASED target question: Does either p or z equal 0?

Statement 1: p = 0
In this case, the answer to the REPHRASED target question is YES, either p or z DOES equal 0
Since we can answer the REPHRASED target question with certainty, statement 1 is SUFFICIENT

Statement 2: z = 0
This also answers our REPHRASED target question perfectly.
Since we can answer the REPHRASED target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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by fskilnik@GMATH » Wed Sep 12, 2018 1:58 pm

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BTGmoderatorDC wrote:Is p + pz = p?

(1) p = 0

(2) z = 0

Source: GMAT Prep
\[?\,\,\,:\,\,\,\,p\left( {1 + z} \right)\,\,\mathop = \limits^? \,\,p\]
\[\left( 1 \right)\,\,\,p = 0\,\,\,\,\, \Rightarrow \,\,\,\,\,\left\langle {{\text{YES}}} \right\rangle \]
\[\left( 2 \right)\,\,\,z = 0\,\,\,\,\, \Rightarrow \,\,\,\,\,\left\langle {{\text{YES}}} \right\rangle \]

This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
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