monopoly question doubt

Posted by bhavya jain on Jun 17, 2014; 6:54am
URL: http://discussion-forum.276.s1.nabble.com/monopoly-question-doubt-tp7592916.html

someone plz tell how to solve this one..
A monopolist faces the demand curve q = 90 - p/2, where q is the number of units sold and p is the price in dollars. She has quasi-fixed costs, C, and constant marginal costs of $20 per unit of output. Therefore her total costs are C + 20q if q > 0 and 0 if q = 0. What is the largest value of C for which she would be willing to produce positive output?