A monopoly is considering selling several units of a homogeneous product as a single package. A typical consumer's demand for the product isQ^d= 80 - .5P, and the marginal cost of production is $100.

a. Determine the optimal number of units to put in a package.

30units

b. How much should the firm charge for this package?

$

I have the answer for A but having trouble with B.... and the answer is not 900