Question

What is the solution of the pair of linear equations $x+y=18$ and $x-2y=0$?

• A. $x=12\&y=6$
• B. $x=6\&y=12$
• C. $x=11\&y=7$
• D. $x=7\&y=11$

Answer 1

The correct option is A $x=12\&y=6$

Given $x+y=18---\left(i\right)$ and
$x-2y=0---\left(ii\right)$
Here, we use substitution method to solve the given system of equations.

From $\left(ii\right)$ we get $x=2y$

Substitute the value of $x$ in $\left(i\right)$

$⟹2y+y=18$
$⟹3y=18$
$⟹y=6$

Substitute the value of $y$ in $\left(i\right)$
$⟹x+6=18$
$x=12$

$\therefore x=12\&y=6$