Question

The length of a hall is 5 m more than its breadth .If the area of the floor of the hall is 84 $m^2$ ,what is the length of the hall?

Answer 1

Let the breadth of the hall be $x$ metres
Then the length of the hall is $(x+5)$ metres
The area of the floor = $x(x+5)$ $m^2$
Therefore $x(x+5)=84$
So $x^2+5x-84=0$
So $(x+12)(x-7)=0$
This gives $x=7$ or $x=-12$
Since the breadth of the hall cannot be negative we reject x = -12 and take x = 7 only
Thus breadth of the hall = 7 metres and length of the hall = (7 + 5) i. e. 12 metres