BrentGMATPrepNow
If 2x + y > 1, and 5 + 4y < x, which of the following
must be true?
A) x < 0
B) y < 0
C) y > 0
D) x < y
E) y < x
When a question provides us with two inequalities, you may be able to apply a property that says the following:
If the inequality symbols of two inequalities are facing the SAME DIRECTION, then we can ADD those inequalities (for more on this, see the video below)
Given:
2x + y > 1
5 + 4y < x
Rewrite the bottom equation as follows:
2x + y > 1
x > 5 + 4y
Subtract 4y from both sides of the bottom inequality:
2x + y > 1
x - 4y > 5
ADD the inequalities to get: 3x - 3y > 6
Divide both sides of the inequality by 3 to get: x - y > 2
At this point, we can conclude that
x > y (aka
y < x).
Answer: E
Aside: If you're not convinced, just follow these steps:
Take: x - y > 2
Add a second inequality: x - y > 2 > 0
This means: x - y > 0
Add y to both sides to get: x > y
Answer: ERELATED VIDEO