Integers

[ketkoag]

If y is an integer and y = |x| + x, is y = 0?
(1) x < 0
(2) y < 1

OA: D
How??

[rs2010]

Eq will give

y=2x if x>0
=0 if x<0

A says X<0 so you know y = 0

B says Y<0, since it is an interger so lets take integer less than 0
which is possible when X is less than 0.


SO D.

[cm47323]

We have two possibilites
If x is negative, y = abs(x) + x = 0, one x is positive, the other negative
If x is positive, y = abs (x) + x = 2x

(1) x < 0. y=0. logic above, Sufficient
(2) y < 1. This tripped me up initially, but the key is that y is an integer, so y<=0. Since y can't be negative. y=0. Sufficient

D

[ketkoag]

please lemme know why y can't be negative if we consider statement 2 coz if x is negative then y is negative. Please elaborate.

[cm47323]

If x is negative, y = abs(x) + x = 0, one x is positive, the other negative
If x is positive, y = abs (x) + x = 2x

By this logic, Y can never be negative. It has nothing to do with the information in (2). 2 just mandates that y=0