Question

The length of a rectangular field is three times its breadth. If the area of the field is 147 sq. metres, then what is the length of the field (in metres)?

• A. 21

Answer 1

The correct option is A 21
Let the breadth of a rectangle be $xm$.
Then, the length equals $3xm$.

Area of a rectangle equals the product of length and breadth.
$\Rightarrow 147m^2=x\times 3x=3x^2$
$\Rightarrow x^2=49m^2$
$x=\pm 7m$

Since breadth cannot be negative, we have $x=7$.

Length of the field is thrice its breadth. Hence, length is $21m$.