mangamma wrote:
If a/b<c/d & bd < 0, which of the following inequalities must be true?
I. ad -bc < 0
II. bc -ad > 0
III. ad -bc > 0
A. I only
B. II only
C. III only
D. I and II
E. II and III
\(\frac{a}{b}<\frac{c}{d}\)
Since bd < 0,, we can multiply the inequality by bd and change the inequality sign..
\(bd*\frac{a}{b}>bd*\frac{c}{d}......ad>bc...ad-bc>0\)
Option III is exactly the same, so correct..
let us see the other options..
I. ad -bc < 0...opposite of ad-bc>0..Not true
II. bc -ad > 0...bc>ad or ad-bc<0...Same as option I..Not true
C
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44% (02:14) correct 
