Question

Solve for $x$ and $y$ by using method of substitution :
$0.2x+0.3y=1.3$; $0.4x+0.5y=2.3$

• A. $-2,-3$
• B. $2,-3$
• C. $2,3$
• D. $-2,3$

Answer 1

The correct option is C $2,3$

$0.2x+0.3y=1.3\Rightarrow 2x+3y=13$

$\Rightarrow x=\frac{13-3y}{2}$

and

$0.4x+0.5y=2.3\Rightarrow 4x+5y=23$

$\Rightarrow 4\left(\frac{13-3y}{2}\right)+5y=23$

$\Rightarrow 26-6y+5y=23$

$\Rightarrow 3=y$

$\therefore x=\frac{13-3\times 3}{2}=2$