csat-suneung 2015 Q18

csat-suneung · South-Korea · csat__math-A 4 marks Combinations & Selection Counting Integer Solutions to Equations
How many ordered pairs $( x , y , z , w )$ of non-negative integers satisfy the system of equations $$\left\{ \begin{array} { l } x + y + z + 3 w = 14 \\ x + y + z + w = 10 \end{array} \right.$$ ? [4 points]
(1) 40
(2) 45
(3) 50
(4) 55
(5) 60
How many ordered pairs $( x , y , z , w )$ of non-negative integers satisfy the system of equations
$$\left\{ \begin{array} { l } 
x + y + z + 3 w = 14 \\
x + y + z + w = 10
\end{array} \right.$$
? [4 points]\\
(1) 40\\
(2) 45\\
(3) 50\\
(4) 55\\
(5) 60