Answer:
90 engines must be made to minimize the unit cost.
Step-by-step explanation:
Vertex of a quadratic function:
Suppose we have a quadratic function in the following format:

It's vertex is the point 
In which


Where

If a>0, the minimum value of the function will happen for 
C(x)=x²-180x+20,482
This means that 
How many engines must be made to minimize the unit cost?
x value of the vertex. So

90 engines must be made to minimize the unit cost.
The Shape in this question is a cylinder
And the formula for finding the L.S.A of a cylinder is 2*pie*r*h
From the question, we are given the diameter so to get the radius we will divide the value for diameter by 2
D = 10/2
=5
Now, 2*3.14*5*4
L.S.A =125.6
It’s the second one, 65.4
V=1
6πd3=1
6·π·53≈ 65.44985in³
Answer:
The expected number of men in the delegation is 0.86.
Step-by-step explanation:
Number of men = 3
Number of women = 4
A delegation of 2 is selected.
Let X be the number of men selected. So, the possible values of X are 0,1,2.



The expected number of men in the delegation is




Therefore, the expected number of men in the delegation is 0.86.