Subject: General Aptitude · Chapter: Number System · Exam: · Marks: · Difficulty:
If x and y are negative, then which of the following statements is/are always true? I. x + y is positive. II. xy is positive. III. x – y is positive.
(a)I only
(b)II only
(c)III only
(d)I and III only
Answer
Answer (as printed): B
Explanation
If x < 0 and y < 0, then clearly xy > 0. So, whenever x and y are negative, then xy is positive. Note that (x < 0, y < 0) does not imply that (x + y) is positive. e.g. If x = – 2 and y = – 3 , then (x + y) = – 5 < 0. Note that (x < 0, y < 0) does not imply that (x – y) > 0. e.g. If x = – 5 and y = – 2, then x – y = – 5 – (– 2) = – 5 + 2 = – 3 < 0.
Explanation as extracted from the printed page; notation may be imperfect.