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.
Answer:
Option c. Correlational
Explanation:
Correlational research is basically a method of carrying out a research where an experiment can not be conducted and where a researcher has to figure out that whether the two variable are in association with each other and if these are related then in what way the association between these two exists without any manipulation from the researcher's end.
It seeks to understand, measure and make assessment of the relationship or
association between these variables but can not find out if a variable is caused by the other variable.
Answer:
Hari didn't plan to go abroad
Explanation:
Abroad planned to go to hari.
Answer:
Because the light reflects multiple times until it gets to the Cassegrain focus.
Explanation:
The Cassegrain design can be seen in a reflecting telescope. In this type of design the light is collected by a concave mirror, and then intercepted by a secondary convex mirror, and sends it down to a central opening in the primary mirror (concave mirror), in which a detector is placed (Cassegrain focus)
Since, the light is reflected many times due to Cassegrain design, that leads to shorter telescopes.