story problem

Question

 A computer notebook manufacturer has a daily fixed cost of $10,500 and a marginal cost of $210 per notebook. Y=210x+10,5000.

Find the average cost of a computer notebook assuming that 50 notebooks are manufactured each day?

 

How many notebooks should be manufactured each day so that the average cost per notebook is $315? 

 

Answer 1

Y/x = average cost = total cost divided by quantity = (210x +10,5000)/x

= 210 + 105000/50 = 210 + 210 = $420 per notebook

For Y/x = $315

210 + 10,500/x = 315

10,500/x = 315-210 = 105

x= 10,500/105 = 100 notebooks