Data Sufficiency (DS) | Re: Martha and Susan have an equal number of cats. If Martha gives one of

Given :
Let no. of cats Martha and susan have initially = x

After change
No of cats Martha has = x-1
No of cats Susan has = x+1

1) By given information we can form equation :
No. of cats Martha has after change * no of cats Susan has after change = product of no. of cats they initially had -1
(x-1)(x+1) = x^2 -1
equation is true. But it does not give any new information. Already given in question stem

1) By given information we can form equation :
No. of cats Susan has after change - No. of
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