DS

[danjuma]

Are the integers Z and F to the right of 0 on the numberline?

1. The product of Z and F is positive

2. The sum of Z and F is positive

[shovan85]

IMO C

1: z*f > 0
z,f <0 or z,f > 0 Not suff

2: z+f > 0
z,f> 0 or one of them can be -ve. Not Suff.

Combine 1 and 2 both have to be +ve then only z*f > 0 and z+f > 0
thus right to zero.

[selango]

stmt1,

The product of Z and F is positive

This means Z&F are both negative or both postive.

Insuff

stmt2,

The sum of Z and F is positive.

There are 3 scenarios in this case.

Z=+ve,F=+ve-->Z&F are both right of 0

Z=-ve,F=+ve,F+Z=+ve-->Only F is right of 0

Z=+ve,F=-ve,F+Z=+ve-->Only Z is right of 0

Insuff

Combining 1 and 2,

To satisfy both conditions,Z and F must be both positive.


Suff

Pick C

[clock60]

here my answer is C
(1) f*z>0 possible in two cases
f>0 z>0, ( both to the right of zero), or

f<0, z<0 (both to the left of 0), so 1 st insuff

(2) also insuff (f+z)>0 if

f>0, z>0,-here to the right of 0
but it can be that f>0, z<0 and sum also +ve (2+(-1)=1
also insuff
both st are valid for z>0, f>0, so suff