samirpandeyit62 wrote:Stat 1: 3y^2+7y = x

i.e y(3y+7) =x

so x is a multiple of y

stmt 2: x^2 - x is a multiple of y

so x(x-1) is a multiple of y

so y is a factor of x(x-1)

now we cannot say that x is a multiple of y i.e here x may be a multiple of y or it may be x-1

So ans should be A

girish3131 wrote:no no...

my point is that B too suffiecient irrespective any value of X

kstv wrote:x and y are integers greater than 1, is x a multiple of y ?
can be express x = ky where k can be any constant
1) 3y²+7y = x y(3y+7) = x
means y multiplied by (3y+7) = x let (3y+7) = k as k can be any constant
yk = x Suff.
2) x²-x is a multiple of y
so x(x-1) = ky where k can be any constant
x = k/(x-1) *y as x > 1 ( all the while u wonder why this fact was mentioned.)
k / (x-1) will not always be an integer.
if it was given x < 1 eg. 1/2 then k/(x-1) = 2k then x= 2k.y then Suff
but now it's Insufficient.

IMO A

girish3131 wrote:

kstv wrote:x and y are integers greater than 1, is x a multiple of y ?
Is the assumption I am making too sweeping
please point out the flaw .