Solve the System by Using Either the Substitution Method or the Elimination-By-Addition

Multiple Choice

Solve the system by using either the substitution method or the elimination-by-addition method, whichever seems more appropriate. $\left( \begin{array} { lll } y &=& 3 x \\0.31 x &+& 0.09 y &= &232\end{array} \right)$

A) (600, 1,800)
B) (400, 1,200)
C) dependent
D) inconsistent