A group of venture investors is considering putting money into Lemma Books, which wants to produce a new reader for electronic books. The variable cost per unit is estimated at $250, the sales price would be set at twice the VC/unit, or $500, and fixed costs are estimated at $750,000. The investors will put up the funds if the project is likely to have an operating income of $500,000 or more. What sales volume would be required in order to meet the minimum profit goal?