Answer:
1006
Step-by-step explanation:
Take proportion, p = 62%
n = (Z² * pq) / M.E²
Margin error = 0.03
p = 62% = 0.62
q = 1 - p = 1 - 0.62 = 0.38
Zcritical at 95% = 1.96
n = (1.96² * (0.62*0.38)) / 0.03²
n = 0.90508096 / 0.0009
n = 1005.6455
n = 1006
Sample size = 1006
The greates amount of pieces he would be able to use would be 9 because 8 divided by 5/6= 9 and 3/5.the 3/5 piece is too short.
Steps to solve:
15 + 2a = 35
~Subtract 15 to both sides
2a = 20
~Divide 2 to both sides
a = 10
Best of Luck!
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.