If x and y are positive integers, are x and y consecutive?
1) x+y=3
2) x-y=1
Source : Math Revolution
Official Answer : D
1) x+y=3
2) x-y=1
Source : Math Revolution
Official Answer : D
Statement 1: The only positive integers that will sum to 3 are 1 and 2, so YES x and y must be consecutive. Sufficient.ziyuenlau wrote:If x and y are positive integers, are x and y consecutive?
1) x+y=3
2) x-y=1
Source : Math Revolution
Official Answer : D
Statement 2: Add y to both sides to get x = 1 + y. This is the algebraic definition of consecutive integers. If x and y are integers, and x = 1 + y (or y = 1 + x) then x and y must be consecutive integers. You could also see this by plugging in numbers. (y = 1 and x = 2; y = 2 and x = 3, etc.) No matter what, x and y will always be consecutive integers, yielding a definitive YES. Sufficient.
The answer is D
