zytel corporation produces cleaning compounds and solutions for industrial and household use. while most of its products are processed independently, a few are related. grit 337, a coarse cleaning powder with many industrial uses, costs $3.00 a pound to make and sells for $4.20 a pound. a small portion of the annual production of this product is retained for further processing in the mixing department, where it is combined with several other ingredients to form a paste, which is marketed as a silver polish selling for $5.70 per jar. this further processing requires 1/4 pound of grit 337 per jar. costs of other ingredients, labor, and variable overhead associated with this further processing amount to $2.10 per jar. variable selling costs are $0.50 per jar. if the decision were made to cease production of the silver polish, $8,700 of mixing department fixed costs could be avoided. zytel has limited production capacity for grit 337, but unlimited demand for the cleaning powder. required: calculate the minimum number of jars of silver polish that would have to be sold to justify further processing of grit 337.