Question

9) The breadth of a rectangle is P units. The length is 3 less than 5 times its breadth. Find the length in
terms of its breadth.
​

Answer 1

Step-by-step explanation:

Let the breadth of the rectangle be x cm.

Then, length = 3x cm

New breadth =(x+5) cm

New length =(3x−3)cm

Then, (x+5)(3x−3)−3x×x=57

⇒3x

2

+12x−15−3x

2

=57

⇒12x=57+15=72⇒x=6

∴ Breadth = 6 cm, Length = 18 cm

Perimeter =2(6cm+18cm)=2×24cm=48 cm

Answer 2

Answer:

Let the breadth of the rectangle be x cm.

Then, length = 3x cm

New breadth =(x+5) cm

New length =(3x−3)cm

Then, (x+5)(3x−3)−3x×x=57

⇒3x

2

+12x−15−3x

2

=57

⇒12x=57+15=72⇒x=6

∴ Breadth = 6 cm, Length = 18 cm

Perimeter =2(6cm+18cm)=2×24cm=48 cm