Question

From the following figure, we can say:

$0.9x+0.5y=6;0.7x+0.7y=5.6$

• A. $x=5,y=3$
• B. $x=4,y=3$
• C. $x=1,y=3$
• D. $x=2,y=3$

Answer 1

The correct option is A $x=5,y=3$

$0.9x+0.5y=6$ .....(i)
$0.7x+0.7y=5.6$ ....(ii)
On multiplying both equations by $10$. we get,
$9x+5y=60$ .....(iii)
$7x+7y=56\Rightarrow x+y=8$ ....(iv)
Multiplying equation (iv) by $5$ . we get,
$5x+5y=40$ .....(v)
Subtracting (v) from (iii). we get,
$4x=20\Rightarrow x=5$
Substitute $x=5$ in equation (iii). we get,
$9\left(5\right)+5y=60$
$\Rightarrow 5y=15\Rightarrow y=3$
$\therefore x=5,y=3$