BTGModeratorVI wrote: ↑Sun Jul 19, 2020 1:46 pm
If x and n are integers, is the sum of x and n less than zero?
(1) x + 3 < n – 1
(2) -10x > 10n
Answer:
B
Source: Manhattan prep
Target question: Is x + n < 0?
Given: x and n are integers
Statement 1: x + 3 < n – 1
Add 1 to both sides to get: x + 4 < n
In other words, n is GREATER than 4 more than x
There are several values of x and n that satisfy this condition. Here are two:
Case a: x = 1 and n = 6, in which case x + n = 7. In this case,
x + n > 0
Case b: x = -10 and n = 0, in which case x + n = -10. In this case,
x + n < 0
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: -10x > 10n
Add 10x to both sides to get: 0 > 10x + 10n
Divide both sides by 10 to get:
0 > x + n. PERFECT! This is precisely what the target question is asking.
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer = B
