Any experts care to explain how to solve the (2) condition?
we are given -1 < ab < 0.
Since a < -1, we know it is always negative. Lets divide every term by a, remembering to flip the inequality because we are dividing by a negative.
-1/a > b > 0.
Since a is always negative, -1/a is always postive so we can say.
1/|a| > b > 0.
Since a < -1, the magnitute of a is always greater than 1 and hence, the fraction 1/|a| is always less than 1 but positive. Hence 1 > b > 0.
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993