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If it is true that z < 8 and 2z > -4, which of the fol

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If it is true that z < 8 and 2z > -4, which of the fol

by BTGmoderatorLU » Sun Mar 04, 2018 12:07 pm
If it is true that z < 8 and 2z > -4, which of the following must be true?

A. -8 < z < 4
B. z > 2
C. z > -8
D. z < 4
E. None of the above

The OA is C.

Can I say, z < 8 and 2z < -4 = z < -2, then -2 < z < 8, right?

Only C is always true, as ANY z from the TRUE range, -2 < z < 8, will be greater than -8.

Experts, any suggestion about this PS question? Thanks in advance.
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by mbawisdom » Sun Mar 04, 2018 2:04 pm
LUANDATO wrote:If it is true that z < 8 and 2z > -4, which of the following must be true?

A. -8 < z < 4
B. z > 2
C. z > -8
D. z < 4
E. None of the above

The OA is C.

Can I say, z < 8 and 2z < -4 = z < -2, then -2 < z < 8, right?

Only C is always true, as ANY z from the TRUE range, -2 < z < 8, will be greater than -8.

Experts, any suggestion about this PS question? Thanks in advance.
I would have set it up the same way you did. You are correct in saying that -2 < Z < 8. Further you are correct in saying that C is true. Every possible value of Z is greater than -8.

A) doesn't hold --> test z = 5
B) doesn't hold --> test z = 1
D) doesn't hold --> test z = 5
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by Brent@GMATPrepNow » Sun Mar 04, 2018 2:26 pm
LUANDATO wrote:If it is true that z < 8 and 2z > -4, which of the following must be true?

A. -8 < z < 4
B. z > 2
C. z > -8
D. z < 4
E. None of the above

The OA is C.

Can I say, z < 8 and 2z < -4 = z < -2, then -2 < z < 8, right?

Only C is always true, as ANY z from the TRUE range, -2 < z < 8, will be greater than -8.

Experts, any suggestion about this PS question? Thanks in advance.
Hi LUANDATO,

Your conclusion, -2 < z < 8, is perfect.
So, if z is BETWEEN -2 and 8, then z must be greater than -8

Answer: C

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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GMAT/MBA Expert

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Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
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GMAT Score:770

by Brent@GMATPrepNow » Sun Mar 04, 2018 2:26 pm
LUANDATO wrote:If it is true that z < 8 and 2z > -4, which of the following must be true?

A. -8 < z < 4
B. z > 2
C. z > -8
D. z < 4
E. None of the above

The OA is C.

Can I say, z < 8 and 2z < -4 = z < -2, then -2 < z < 8, right?

Only C is always true, as ANY z from the TRUE range, -2 < z < 8, will be greater than -8.

Experts, any suggestion about this PS question? Thanks in advance.
Hi LUANDATO,

Your conclusion, -2 < z < 8, is perfect.
So, if z is BETWEEN -2 and 8, then z must be greater than -8

Answer: C

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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