Question

The ratio between the length and breadth of a rectangular field is 5 : 4 if the breadth is 20m less than the length, the perimeter of the field is :
A) 260m
B) 280m
C) 360m
D) none of these

Answer 1

The ratio between the length and breadth of a rectangular field is 5 : 4 if the breadth is 20m less than the length, the perimeter of the field is :
A) 260m
B) 280m
C) 360m
D) none of these

=> Option C

Explanation:

Let length of rectangular field = 5y,
so width = 4y.

From question
5y - 4y = 20m
⇒ x = 20m 
∴ Length = (5 x 20)m = 100 m
Breadth = (4 x 20) m = 80 m 

∴ Perimeter = 2 (100 + 80 ) m = 360 m

Answer 2

The answer is 360m. (option c)

Given:

• Length and Breadth Ratio = 5:4
• Breadth is 20m less than length.

To Find:

• The perimeter of the field.

Solution:

• Let us consider length to be 5x and width as 4x.
• From the question, we get an equation saying 5x-4x = 20m
• x = 20m
• Lenght = 5*20 = 100m
• Breadth = 4*20 = 80m
• The formula to find perimeter is given by
• Perimeter = 2(l+b) = 2*(100+80) =2*180 = 360
• Perimeter = 360m

Perimeter of the field is 360m.