CA Foundation · Quantitative Aptitude · Linear Inequalities
If a < b and c < 0, which of the following must be true for real numbers a, b and c?
The statement ac > bc must be true. When both sides of an inequality are multiplied by a negative number, the inequality sign reverses, so a < b becomes ac > bc when c is negative.
- Aac < bc
- Bac > bcCorrect
- Ca + c > b + c
- Da/c < b/c
Explanation
Multiplying both sides of an inequality by a negative number reverses its direction, so a < b gives ac > bc. Adding c keeps the sign, so a + c < b + c, making option C wrong. Dividing by a negative c also reverses it, so a/c > b/c, making option D wrong.
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