If X Y and Z is a positive number, which of the following relationsh

Question

If X > Y and Z is a positive number, which of the following relationship is not true ?

A. XZ > YZ 
B. Z-X > Z-Y 
C. X-Z > Y-Z 
D. X/Z > Y/Z
E. X+Z > Y+Z

CareerGeek · Answer

A. XZ > YZ --> XZ - YZ > 0 --> Z(X - Y) > 0 --> Positive*Positive = Positive -- True B. Z-X > Z-Y --> 0 > Z - Y - Z + X --> X - Y < 0 --> X < Y -- NOT True C. X-Z > Y-Z --> X - Z - Y + Z > 0 --> X - Y > 0 --> X > Y -- True D. X/Z > Y/Z --> X/Z - Y/Z > 0 --> (X - Y)/Z > 0 00> Positive/Positive = Positive -- True E. X+Z > Y+Z --> X > Y -- True IMO Option B Pls Hit Kudos if you like the solution

freedom128 · Answer

If X > Y and Z is a positive number, which of the following relationship is not true ?

Try Z=2 for all answers

A. XZ > YZ 
2X > 2Y --> X>Y  (TRUE) 
 
B. Z-X > Z-Y
2-X > 2-Y --> Y > X  (FALSE!! The correct answer)

C. X-Z > Y-Z 
X-2 > Y-2 --> X > Y  (TRUE)

D. X/Z > Y/Z
X/2 > Y/2 --> X > Y  (TRUE)

E. X+Z > Y+Z 
X+2 > Y+2 --> X > Y  (TRUE)

Answer is (B)

pls Hit Kudos if you like the solution

eakabuah · Answer

x>y, and z is a positive number. Let x=4,y=3 and z=2
We are to determine the relationship that is not true. 
A. xz>yz i.e. 8>6; True
B. z-x>z-y i.e. (-2)>(-1); not true. 
C. x-z>y-z i.e. 2>1; true. 
D. x/z>y/z i.e. 2>3/2 true. 
E. x+z>y+z i.e. 6>5; true.

The answer is therefore B.

Posted from my mobile device

ScottTargetTestPrep · Answer

Since X > Y, then -X < -Y and hence Z - X < Z - Y. So choice B, Z - X > Z - Y, is not true. Answer: B

If X > Y and Z is a positive number, which of the following relationsh

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions