posted by mathstudent05 .
Assume that each situation can be expressed as linear cost function. Find the cost function in each case.
Marginal cost $90;150items cost $16,000 to produce.
this is what i end up.
That is correct if the cost function is linear, which is probably what your teacher wanted. However, in reality, the cost funtion is seldom linear. Cost per item diminishes usually with volume.