Voip telephone, inc., provides local and long distance telephone service in the toledo, ohio market.
the company faces the following segmented demand and marginal revenue curves for its service: over the range of 0 to 25(000) customers per month: p1 = 6 - 0.04q mr1 = ? tr1/? q = 6 - 0.08q

when output exceeds 25(000) customers per month: p2 = 8 - 0.12q mr2 = ? tr2/? q = 8 - 0.24q

the company's total cost is as follows: tc = 2.50 + 1.50q + 0.02q2 where p is price (in dollars), q is output (in thousands), and tc is total cost (in thousands of dollars).

how much could marginal cost rise before the optimal price increase?