Carcass wrote:
If a + (1/b) = 400, and a < -300, then which of the following must be true?
A) b > -700
B) b > 1/(-100)
C) b > 1/ 300
D) b > 700
E) b < 1/700
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITIONGRE - Math BookGiven: a + (1/b) = 400
Subtract 1/b from both sides to get:
a = 400 - 1/b Also given:
a < -300
Replace
a with
400 - 1/b to get:
400 - 1/b < -300
Add 1/b to both sides: 400 < -300 + 1/b
Add 300 to both sides: 700 < 1/b
IMPORTANT: 700 < 1/b, then
b must be POSITIVESince b is POSITIVE, we can safely multiply both sides of the inequality by b to get: 700b < 1
Finally, divide both sides by 700 to get: b < 1/700
Answer: E