Question

Solve the following pair of linear equations :
$0.2x+0.3y=1.3$
$0.4x+0.5y=2.3$

Answer 1

$0.2x+0.3y=1.3......\left(1\right)$

$0.4x+0.5y=1.3......\left(2\right)$

Derive the value of $y$ from equation (1)

$y=\frac{1.3-0.2x}{0.3}$ ......(3)

Substitute value of $y$ in equation(3)

$0.4x+0.5\left(\frac{1.3-0.2x}{0.3}\right)=2.3$

$\Rightarrow$$0.12x+0.5\left(1.3-0.2x\right)=0.69$

$\Rightarrow$$0.12x+0.65-0.1x=0.69$

$\Rightarrow$$0.02x=0.64$

$\Rightarrow$$x=32$

Substitute value of $x$ in equation (3)

$y=\frac{1.3-0.2\left(32\right)}{0.3}$

$=\frac{1.3-6.4}{0.3}$

$=-17$

So, $x=32$ and $y=-17$