Data Sufficiency (DS) | If xy = z, what is the value of y ?

Another approach

In this question, any variable can take any number with any sign. There is no constraint on anyvariable.

(2) x > 1

No info about z or relations

Insufficient

(1) x = 3z.........\(z =\frac{1}{3} x\)

Substitute in\(xy = z\)

\(x y = \frac{1}{3} x\)
case 1: Let x = 0.........LHS = RHS =0 ....then y can take any number. y could be 0, 1, -10, 1000...etc

case 2: Let x = any number other than 0........ then x canceled out from both sides............
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