Answer is D :)
hope it helps
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.
Answer: they can rent the room for less than 6 hours.
Step-by-step explanation:
Let x represent the possible amounts of time in which they can rent the room.
There is a reservation fee of $47 and an additional hourly fee of $7.40. This means that the total cost of renting the room for x hours would be
47 + 7.4x
The math club wants to spend less than $91.40 on renting the room. This would be expressed as
47 + 7.4x < 91.4
7.4x < 91.4 - 47
7.4x < 44.4
x < 44.4/7.4
x < 6
181 is the only palindrome that has digits that when multiplied together give you 8.
Hope that helps :)
Answer:
33 years
Step-by-step explanation:
I think you might have made a typo, but it would still be 33 if the mean age stays the same.