If in a rectangle, the length is increased and breadth reduced each by 2 units, the area is reduced by 28 square units.
If in a rectangle, the length is increased and breadth reduced each by 2 units, the area is reduced by 28 square units. If, however the length is reduced by 1 unit and the breadth increased by 2 units, the area increases by 33 square units. Find the area of the rectangle.
Let the length and breadth of the rectangle be
and
units respectively
Then, area of rectangle
square units
If length is increased and breadth reduced each by
units, then the area is reduced by
square units
$\begin{aligned} &(x+2)(y-2)=x y-28 \\ \Rightarrow & x y-2 x+2 y-4=x y-28 \\ \Rightarrow &-2 x+2 y-4+28=0 \\ \Rightarrow &-2 x+2 y+24=0 \\ \Rightarrow & 2 x-2 y-24=0 \end{aligned}$
Therefore, ![]()
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Then the length is reduced by
unit and breadth is increased by
units then the area is increased by
square units
$(x-1)(y+2)=x y+33$
$\Rightarrow x y+2 x-y-2=x y+33$
$\Rightarrow 2 x-y-2-33=0$
$\Rightarrow 2 x-y-35=0$
Therefore, $2 x-y-35=0 \quad \ldots \ldots(i i)$
Thus we get the following system of linear equation
$2 x-2 y-24=0$
$2 x-y-35=0$
By using cross multiplication, we have
$\frac{x}{(-2 \times-35)-(-1 \times-24)}=\frac{y}{(2 \times-35)-(2 \times-24)}=\frac{1}{(2 \times-1)-(2 \times-2)}$
$\frac{x}{70-24}=\frac{-y}{-70+48}=\frac{1}{-2+4}$
$\frac{x}{46}=\frac{-y}{-22}=\frac{1}{2}$
$x=\frac{46}{2}$
$x=23$
and
$y=\frac{22}{2}$
$y=11$
The length of rectangle is
units.
The breadth of rectangle is
units.
Area of rectangle =length
breadth,
$=x \times y$
$=23 \times 11$
$=253$ square units
Hence, the area of rectangle is
square units