The nearest whole number is 28
20.75 because if you add 4.85+7.95+7.95 add that you get 20.75
We presume your cost function is
c(p) = 124p/((10 +p)(100 -p))
This can be rewritten as
c(p) = (124/11)*(10/(100 -p) -1/(10 +p))
The average value of this function over the interval [50, 55] is given by the integral

This evaluates to
(-124/55)*(ln(65/60)+10ln(45/50)) ≈ 2.19494
The average cost of removal of 50-55% of pollutants is about
$2.19 hundred thousand = $219,000
Answer:
ANSWER
y = 3x + 6.50
EXPLANATION
The $3 for each downloaded movie is the unit rate of change.
This is represent the slope of the linear function that models this situation.
The monthly fee of monthly fee of $6.50 the constant rate.
It represents the y-intercept of the function.
The linear function is given by
y = mx + by=mx+b
The correct choice is y = 3x + 6.50