Cantel Company produces cleaning compounds for both commercial and household customers. Some of these products are produced as part of a joint manufacturing process. Some of these products are produced as part of a joint manufacturing process.

For example, GR37, a coarse cleaning powder meant for commercial sale costs $1.60 a pound to make and sells for $2.00 per pound. A portion of the annual production of GR37 is retained for further processing in a separate department where it is combined with several ingredients to form SilPol, which is sold as a silver polish, at $4.00 per unit. The additional processing requires pound of GR37 per unit; additional processing costs amount to $2.50 per unit of SilPol produced. Variable selling costs for this product average $0.30 per unit. If production of SilPol were discontinued, $5,600 of costs in the processing department would be avoided. Cantel has, at this point, unlimited demand for, but limited capacity to produce, product GR37.

Calculate the minimum number of units of SilPol that would have to be sold in order to justify further processing of GR37.