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BTGModeratorVI
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Target question: Is x < y?BTGModeratorVI wrote: ↑Thu Jun 11, 2020 8:36 amIs x < y?
1) x - y < -4
2) -2x > -2y
Answer: D
Source: Math Revolution
Statement 1: x - y < -4
Add y to both sides to get: x < y - 4
IMPORTANT: we know that y - 4 < y
So, we can combine y - 4 < y with x < y - 4 to get: x < y - 4 < y
From this we can conclude that x < y
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: -2x > -2y
Divide both sides of the inequality by -2 to get: x < y [aside: when we divide both sides of an inequality by a negative value, we must switch the direction of the inequality]
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer: D
