Answer:
(a) The strip should be 5ft wide
(b) The strip around the outside field is 10ft wide.
Step-by-step explanation:
Given:
Length of the rectangular field, L= 200 ft
width of the rectangular field, w = 100 ft
Area of the rectangular field, A = 200ft x 100ft = 20000 ft^2
let the width of the strip = x
The strip around the outside field = 2x
If the field is increased by 15.5%
New area of the field = 1.155 x 20000 = 23,100 ft^2
The increase in area of the field = 3,100 ft
3,100 = New area of field - old area of the field
3100 = (200 + 2x)(100 + 2x) - 20000
3100 = 20000 + 400x 200x + 4x^2 - 20000
3100 = 600x + 4x^2
Divide through by 4
775 = 150x + x^2
x^2 + 150x - 775 = 0
Factorize
(x + 155)(x-5) = 0
x = 5 ft
The strip should be 5ft wide.
The strip around the outside field = 2 x 5 ft = 10 ft
Thus, the strip around the outside field is 10ft wide.
