Question

If the area of a rectangle whose length is twice its breadth is $800$ m${}^2$, then the length and breadth of the rectangle are:

• A. $60$ m and $20$ m
• B. $40$ m and $20$ m
• C. $80$ m and $10$ m
• D. $100$ m and $8$ m

Answer 1

The correct option is B $40$ m and $20$ m

Let the breadth of rectangle be $x$.

The length will be $2x$.

Given, area of rectangle is $800$ m${}^2$.

Area of rectangle is $l\times b$

Therefore, $x\times 2x=800$

$\Rightarrow 2x^2=800$

$\Rightarrow x^2=400$

$\Rightarrow x=20$

Breadth of rectangle is $20$ m.

Now, length of rectangle $=2x=2\times 20=40$ m.