GreenlightTestPrep wrote:
\(x\) and \(y\) are integers, and \(x + y > 0\). If \(5x - 1\) is a multiple of \(4\), and \(4y + 2\) is a multiple of \(6\), what is the smallest possible value of \(x + y\)?
A) 0
B) 1
C) 3
D) 5
E) 7
The key here is to recognize that multiples of a value need not necessarily be positive.
For example some multiples of 5 include: 5, -15, 0, 55, -20 etc
So from here it's simply a matter of finding some values that satisfy the given conditions.
If \(5x - 1\) is a multiple of \(4\), then it could be the case that x = -3, since \(5(-3)-1 = -16\) and -16 is a multiple of 4.
Likewise, if \(4y + 2\) is a multiple of \(6\), then it could be the case that y = 4, since \(4(4)+2 = 18\) and 18 is a multiple of 6.
So, x + y = (-3) + 4 = 1
So 1 is the smallest possible value of x + y
Answer: B
ASIDE: The answer is not A, because we are told that \(x + y > 0\).
Cheers,
Brent