Answer:
<em>The least number of items to produce is 41</em>
Step-by-step explanation:
<u>Average Cost</u>
Given C(x) as the cost function to produce x items. The average cost is:

The cost function is:

And the average cost function is:

We are required to find the least number of items that can be produced so the average cost is less or equal to $21.
We set the inequality:

Multiplying by x:

Note we multiplied by x and did not flip the inequality sign because its value cannot be negative.
Adding 20x:


Swapping sides and changing the sign:

Dividing by 41:

The least number of items to produce is 41
C = number of parents
c+9 = number of children
2c+9=25
2c=16
c=8
8 parents, 17 children
Answer:
8 miles.
Step-by-step explanation: