BTGmoderatorDC wrote: ↑Sun Dec 05, 2021 7:20 pm
What is the value of x ?
(1) y - x = y - 6
(2) x + 2y = 10
OA
A
Source: GMAT Prep
Target question: What is the value of x ?
Statement 1: y - x = y - 6
Note: In most cases, there are infinitely many solutions to a linear equation with two variables. However, in this case, one of the variables cancels, leaving us an equation with ONE variable
Subtract y from both sides of the equation to get:
-x = -6
Multiply both sides of the equation by -1 to get:
x = 6
Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: x + 2y = 10
This case, none of the variables cancel, which means there are infinitely many solutions to the equation
x + 2y = 10
Here are two possible solutions:
Case a: x = 0 and y = 5. In this case, the answer to the target question is
x = 0
Case b: x = 10 and y = 0. In this case, the answer to the target question is
x = 10
Since we can’t answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
