If x and y are positive integers, which of the following CANNOT be the greatest common divisor of 35x and 20y?
Select the correct option:	A) 5	B) 5(x-y)	C) 20x	D) 20y	E) 35x
We are looking for a choice that CANNOT be the greatest common divisor of 35x and 20y ...which means 35x and 20y when divided by the answer choice the quotient should not be a integer.   lets check   a. 5 35x/5 = 7x and 20y/5 = 4y both are integers so eliminate   b. 5(x-y) when x 20 /5= 
<gadget id="calculator">20 /5</gadget>
<output>4</output>
4y both are integers so eliminate   b. 5(x-y) when x= 2 and y = 1 it could be be the greatest common divisor ..so eliminate   c. 20x when x = 1 its 20 and 20 cannot be the greatest common divisor of 35x and 20y ...   or 35x/20x = 7/4 which is not a integer.   so answer is 20x.
<result>C</result>
If x and y are positive integers, which of the following CANNOT be the greatest common divisor of 35x and 20y?