Out of a list of mailing addresses, company A has x addresses, company B has y addresses, and companies A and B combined have a total number of addresses equal to 3 times as many as company A has. How many mailing addresses belong to both companies? Choose the correct choice from the following options:	A) x	B) y	C) x + y	D) y - 2x	E) x - 2y
Let s denote the shared addresses between A and B.So A will have distinct x - s addresses and B will have y - s addresses   .   Given "A and B combined have a total number of addresses equal to 3 times as many as company A has"   i.e, x + y - s = 3 x (s is subtracted because it's captured twice)   solve for s and it gives, y - 2x.   Answer is y - 2x
<result>D</result>
Out of a list of mailing addresses, company A has x addresses, company B has y addresses, and companies A and B combined have a total number of addresses equal to 3 times as many as company A has. How many mailing addresses belong to both companies?