Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 20 May 2013, 15:23

# If xy + z = x(y+z), which of the following must be true?

Author Message
TAGS:
Director
Joined: 03 Sep 2006
Posts: 910
Followers: 5

Kudos [?]: 29 [0], given: 33

If xy + z = x(y+z), which of the following must be true?  [#permalink]  23 Jun 2007, 02:33
00:00

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If xy + z = x(y+z), which of the following must be true?

A. x=0 and z=0

B. x=1 and y=1

C. y=1 and z=0

D. x=1 OR y=0

E. x=1 OR z=0

Sorry! I edited the choice D and E. it is not "and".

Last edited by LM on 23 Jun 2007, 06:04, edited 1 time in total.
VP
Joined: 08 Jun 2005
Posts: 1172
Followers: 5

Kudos [?]: 78 [0], given: 0

XY + Z = X(Y+Z)

XY + Z = XY + XZ

X = Z/Z (Z cannot be zero)

X = 1

we are left with B,D - I don't see the difference

Director
Joined: 14 Jan 2007
Posts: 787
Followers: 1

Kudos [?]: 32 [0], given: 0

KillerSquirrel wrote:
XY + Z = X(Y+Z)

XY + Z = XY + XZ

X = Z/Z (Z cannot be zero)

X = 1

we are left with B,D - I don't see the difference

How do you say - Z can't be zero.
Substitute zero in both sides of XY + Z = XY + XZ
The equation is satisfied.
Take example : if I say 5x = y , would you say that x can't be zero because 5 = y/x . But the fact is y and x both can be zero.
VP
Joined: 08 Jun 2005
Posts: 1172
Followers: 5

Kudos [?]: 78 [0], given: 0

vshaunak@gmail.com wrote:
KillerSquirrel wrote:
XY + Z = X(Y+Z)

XY + Z = XY + XZ

X = Z/Z (Z cannot be zero)

X = 1

we are left with B,D - I don't see the difference

How do you say - Z can't be zero.
Substitute zero in both sides of XY + Z = XY + XZ
The equation is satisfied.
Take example : if I say 5x = y , would you say that x can't be zero because 5 = y/x . But the fact is y and x both can be zero.

I stand corrected
Senior Manager
Joined: 04 Jun 2007
Posts: 357
Followers: 1

Kudos [?]: 9 [0], given: 0

The solution should be:
=> XY + Z = X(Y+Z)
=> XY + Z = XY + XZ
=> Z*(X-1)=0
=> Z=0;X=1

We can't do this

KillerSquirrel wrote:
XY + Z = X(Y+Z)

XY + Z = XY + XZ

X = Z/Z (Z cannot be zero)

X = 1

we are left with B,D - I don't see the difference

specifically because Z could be zero.
Director
Joined: 03 Sep 2006
Posts: 910
Followers: 5

Kudos [?]: 29 [0], given: 33

sumande wrote:
The solution should be:
=> XY + Z = X(Y+Z)
=> XY + Z = XY + XZ
=> Z*(X-1)=0
=> Z=0;X=1

We can't do this

KillerSquirrel wrote:
XY + Z = X(Y+Z)

XY + Z = XY + XZ

X = Z/Z (Z cannot be zero)

X = 1

we are left with B,D - I don't see the difference

:?

specifically because Z could be zero.

Yours is the best explanation. Requires less time to think and faster to reach the answer! Thanks
Similar topics Replies Last post
Similar
Topics:
If xy +z = x(y+z) which of the following must be true? A) 3 05 Nov 2006, 17:11
If xy+z = x(y+z), which of the following must be true? 1, 2 09 Dec 2007, 20:08
If xy + z = x(y+z), which of the following must be true? A. 2 23 Dec 2007, 21:47
If xy+z = x(y+z), which of the following must be true? a. 4 31 Mar 2008, 00:36
If xy + z = x(y+z), which of the following must be true? A. 3 18 May 2008, 18:14
Display posts from previous: Sort by