Multiples A

tanyajoseph · Posted: Mon Sep 10, 2007 12:56 pm Post subject: Multiples A

If x and y are integers greater than 1, is x a multiple of y?

1)3y^2+7y = x
2) x^2 - x is a multiple of y

Elaborate explanation would be great Smile

TT · Posted: Mon Sep 10, 2007 3:29 pm Post subject: TT

I think the answer is A.

ri2007 · Posted: Mon Sep 10, 2007 7:15 pm Post subject:

Agree ans should be A

Stat 1) 3y^2+7y = x

3y^ is a multiple of Y, also 7 Y is a multiple of Y so the sum of the two will be a multiple of Y. Since Multiple of Y is = X ans should be yes.

You can plug in diff values and check.

Stat 2) x^2 - x is a multiple of y

Since x^2 - x can be greater than greater than X you cannot determine if X is also a multiple

I have a feeling I have not been able to explain this one properly. Hope it helps ????

samirpandeyit62 · Posted: Mon Sep 10, 2007 8:52 pm Post subject:

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

remainder · Guest