How many ordered pairs $( a , b , c , d )$ of non-negative integers satisfy the following conditions? [4 points] (가) $a + b + c - d = 9$ (나) $d \leq 4$ and $c \geq d$ (1) 265 (2) 270 (3) 275 (4) 280 (5) 285
How many ordered pairs $( a , b , c , d )$ of non-negative integers satisfy the following conditions? [4 points]\\
(가) $a + b + c - d = 9$\\
(나) $d \leq 4$ and $c \geq d$\\
(1) 265\\
(2) 270\\
(3) 275\\
(4) 280\\
(5) 285