iran-konkur 2013 Q144

iran-konkur · Other · konkur-riazi_1392 Not Maths
144- How many ordered pairs $(a, b)$ can we choose with integer and positive coordinates, so that the sum of the first coordinates and the sum of the second coordinates of the two chosen pairs are both even?
(1) $3$ (2) $4$ (3) $5$ (4) $6$
\textbf{144-} How many ordered pairs $(a, b)$ can we choose with integer and positive coordinates, so that the sum of the first coordinates and the sum of the second coordinates of the two chosen pairs are both even?

(1) $3$ \qquad (2) $4$ \qquad (3) $5$ \qquad (4) $6$