Question

The length of rectangle is more than the double of its breadth by 5 cm. If the area of the rectangle is 75 sq.cm. Then the perimeter of the rectangle is --------------- cm.


options
a) 20
b)40
c)28
d)56​

Answer 1

Answer:

40cm

Step-by-step explanation:

Write an algebraic equation for the area of the rectangle:

If breadth =x, then length = (2x+5)

We know that area of a rectangle = length x breadth = 75

Therefore,

(2x+5)(x) = 75

$2x^{2}$ + 5x = 75

Rearrange:

$2x^{2}$ + 5x -75 = 0

Factorise:

(2x+15)(x-5) = 0

Solve:

x = 5 or -7.5

Since, the breadth of a rectangle can’t be negative, we understand that x = 5.

Therefore,

Breadth = x = 5cm

Length = 2x+5 = 15cm

Find the perimeter:

Perimeter of a rectangle = 2(length + breadth) = 2(20) = 40cm

Answer 2

Answer:

The area of a rectangle is (lb)

the equation become 5 into x = 75

so x = 75/5= 15 so the length is 15..

Step-by-step explanation:

so the perimeter of rectangle Is 2l+b .. so 2into 5+15=40

so the correct answer is (b) 40

Hope it's help you dear...