Answer:
Rectangular path
Solution:
As per the question:
Length, a = 4 km
Height, h = 2 km
In order to minimize the cost let us denote the side of the square bottom be 'a'
Thus the area of the bottom of the square, A =
Let the height of the bin be 'h'
Therefore the total area,
The cost is:
C = 2sh
Volume of the box, V = (1)
Total cost, (2)
From eqn (1):
Using the above value in eqn (1):
Differentiating the above eqn w.r.t 'a':
For the required solution equating the above eqn to zero:
a = 4
Also
The path in order to minimize the cost must be a rectangle.