If x = 1 – 2y, what is z?

Question

(1) 5x + 10y + z = 5

(2) x = 17 + 2y

elegantm · Answer

x = 1 – 2y, could be rewritten as
 x + 2y =1

Statement 1  - 5x + 10y + z = 5
z = 5 - 5x -10y
z = 5 - 5(x + 2y)
z = 5 - 5(1)
z = 0
Sufficient

Statement 2  - x = 17 + 2y
As per info given in question stem
x + 2y =1
 If we look closely, we shouldn't be solving the values of x & y since relation between z and x & y is not given 
Thus InSufficient

Hence Answer A

pushpitkc · Answer

From the question stem, since x = 1 – 2y
x+2y = 1
We have been asked to find out the value of z.

From statement 1
(1) 5x + 10y + z = 5
z = 5 - 5x - 10y
z = 5 - 5(x+2y) = 5 - 5(1) from the question stem
z =0(Sufficient)

(2) x = 17 + 2y 
We have values of x and y, but no relation with z.
Since we need to find out the value of z,
we cannot deduce an unique value of z using statement 2 alone(Insufficient)

The answer to this question is  Option A

va95 · Answer

Answer: A

Statement 1: If we put 1-2Y instead of X we get 5(1-2Y)+10Y+Z=5
5-10Y+10Y+Z=5
5+Z=5
Z=0
Statement 2: We put 1-2Y instead of X and get 1-2Y=17+2Y
4Y=-16
Y=-4
No information about Z. Not sufficient
Also, we didn't have to solve this to understand that this statement is not sufficient. The reason is that it doesn't contain any information on Z, neither the problem itself does.

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Chets25 · Answer

If x = 1 – 2y, what is z?

(1) 5x + 10y + z = 5

(2) x = 17 + 2y

Statement 1: replace value of X in the 1st equation, we get
5(1-2y)+10y+z=5
5-10y+10y+z=5
10y gets cancelled out, hence we get Z. Sufficient

Statement 2: Doesn't talk about Z at all and there is no way to find Z, hence insufficient.

Correct Answer:  A

sashiim20 · Answer

Given, x = 1 – 2y ----------- (i)

(1) 5x + 10y + z = 5

5x + 10y -5 = z

5(-1) (-x + 1 - 2y) = z

-5(-x + x) = z  --------------- (Substituting from (i) x = 1 - 2y  )

-5(0) = z

z = 0  --------------- (I is Sufficient)

(2) x = 17 + 2y  --------------(ii)
  x = 1 - 2y  -------------- (i)

Subtracting (i) from (ii) we get value of  x = 18 . From this we can find the value of y. 
Both equations have only 2 variables x and y. Does not contain variable z. Hence We cannot find value of z. --------------- (II is not Sufficient)

Answer (A)...

BrentGMATPrepNow · Answer

Target question :    What is the value of z?

Given :  x = 1 – 2y

Statement 1 : 5x + 10y + z = 5   
Replace  x  with  1 – 2y  to get: 5( 1 – 2y ) + 10y + z = 5
Expand: 5 - 10y + 10y + z = 5
Simplify: 5 + z = 5
Solve,  z = 0 
Since we can answer the  target question  with certainty, statement 1 is SUFFICIENT

Statement 2 : x = 17 + 2y  
No information about z. 
Since we cannot answer the  target question  with certainty, statement 2 is NOT SUFFICIENT

Answer:  A

Cheers,
Brent

sonikavadhera · Answer

The answer is A.

Statement 1: if x is replaced as 1-2y in the equation given, z = 0

Statement 2: no value of Z hence insufficient

Therefore, IMO A

harikrish · Answer

If x = 1 – 2y, what is z?

(1) 5x + 10y + z = 5

(2) x = 17 + 2y

Solution:

Rewriting the question stem, 2y+x=1

Statement 1: 2(2y+x)+z=1, Solving this we get z=3. Sufficient.

Statement 2: Insufficient.

Therefore the correct answer is A.

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If x = 1 – 2y, what is z?

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