$$(x−1)(1−y)=?$$swerve wrote:$$(x−1)(1−y)=?$$
$$(1)\ x+y=xy$$
$$(2)\ x−y=0$$
The OA is A.
I don't have clear this DS question. Please, can any expert help me with it? Thanks.
$$x−1−xy+y =\ ? ---(1)$$
$$(1)\ x+y=xy$$
$$=> (1)\ x+y-xy = 0 ---(2)$$
Plugging in the value of (2) in (1), we get
$$0 −1 =\ -1 ---(1)$$. Sufficient
$$(2)\ x−y =\ 0$$
=> x = y
It can't help it. Insufficient.
The correct answer: A
Hope this helps!
-Jay
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