Bunuel wrote:
If 0 < a < b, is c < 0?
(1) cb < ca
(2) a – b > c
Target question: Is c < 0? Given: 0 < a < b If a < b, then we know that b - a > 0
In other words,
b - a = some positive numberIt also means that
a - b = some negative number Statement 1: cb < ca Subtract ca from both sides to get: cb - ca < 0
Factor: c(b - a) < 0
So, c(
some positive number) < 0
This means that c must be a negative number.
In other words,
c < 0Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: a – b > c So,
some negative number > c
If c is less than
some negative number, then c must be a negative number.
In other words,
c < 0Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer:
ASIDE: For statement 1, once we get to c(
some positive number) < 0, we can also just divide both sides by
some positive number to get c < 0
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