The Official Solution is as follows:


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Qs : Is x a factor of y?

given :
as y/x= 3 i.e. y= 3x,
y could be = 3, 6, 9, 12, 15, 18....

1) x is even

as x is even so
x = 2, 4, 6,
and y= 6, 12, 18,...
we see that x is always a factor of y , y/x = integer. hence sufficient to answer.

2) x > 0
in statement, no information is given whether x is integer or fraction. if it is integer then above case may be valid but in case of fraction it may not be the case.
consider x= 1/3, so y= 3 x 1/3= 1
but 1/3 is not a factor of 1 hence it not always true. not sufficient condition.

Answer is A.

Given : y/x=3

Is x a factor of y? Y/N

Let's consider cases before going for statements.
y=6 x=2 Obvious case.
y=3 x=1
y=-3 x=-1
y=1 x=1/3
y=12 x=4
y=-6 x=-2

Statement 1) x is even
Sufficient. From all the examples above. Fractions cannot be even. So that cannot be the case.

Statement 2) x > 0

y=1 x=1/3 - No
y=12 x=4 - Yes

Sufficient.

Answer (A)
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If y/x = 3, Is x a factor of y?
1) x is even
2) x > 0

#1
x is even ; so value of y would have to be a factor of x ; eg 6/2 ; 18/6 ; 12/4 ; sufficient
#2
x>0
not necessarily sufficient
as y =1 and x = 1/3 ; or any integer value of x & y
insufficient
IMO A