Let length of rectangle = 5k
and breadth of rectangle = 3k

According to the quecation,
5k - 3k = 8

Required area = Lenght x Breadth

Correct Option: C

Let length of rectangle = 5k
and breadth of rectangle = 3k

According to the quecation,
5k - 3k = 8
⇒ 2k =8
∴ k = 4
∴ Lenght = 5k = 5 x 4 = 20 m
Breadth = 3k = 3 x 4 = 12 m

∴ Required area = Lenght x Breadth
= 20 x 12 = 240 sq m

Let length = 2x and breadth = x
According to the question,
2x - x = 5

∴ Required perimeter = 2(2x + x)

Correct Option: A

Let length = 2x and breadth = x
According to the question,
2x - x = 5
⇒ x = 5

∴ Required perimeter = 2(2x + x)
= 6x
= 30 cm

Let l = 4k and b = 9k
Area of rectangle = l x b
144 = 4k x 9k

Perimeter of rectangle = 2(l + b)

Correct Option: A

Let l = 4k and b = 9k
Area of rectangle = l x b
144 = 4k x 9k
⇒ k² = 144/36
⇒ k² = 4
∴ k = 2
∴ l = 8 cm and b = 18 cm

Perimeter of rectangle = 2(l + b)
= 2(8 + 18)
= 2 x 26
= 52 cm

Let length of the rectangular field = 7k m
and breadth of the rectangular field = 2k m

According to the question,
Area of a rectangular field = Length x Breadth
⇒ 3584 = 7k x 2k

Perimeter of rectangle = 2(Length x Breadth)

Correct Option: D

Let length of the rectangular field = 7k m
and breadth of the rectangular field = 2k m

According to the question,
Area of a rectangular field = Length x Breadth
⇒ 3584 = 7k x 2k
⇒ 14 x k² = 3584
⇒ k² = 3584/14 = 256
⇒ k² = 256 = 16 m
∴ Length of rectangular field = 7k = 7 x 16 = 112 m
And breadth of rectangular field = 2 x 16 = 32 m

∴ Perimeter of rectangle = 2(Length x Breadth)
= 2(112 + 32)
= 2 x 144
= 288 m

According to the question,
l/[2(l + b)] = 5/18

Correct Option: C

According to the question,
l/[2(l + b)] = 5/18
⇒ 10l + 10b = 18l = 10b
⇒ l/b = 10/8 = 5/4
∴ l : b = 5 : 4
Hence, ratio of length and breadth of a rectangle is 5 : 4