why do they multiply 387000 by 2/3 in this problem?

Bluebird Sports. Inc., produces high-quality sports equipment. The company's Racket Division manufactures two tennis rockets-the Standard and the Deluxe-that are widely used in amateur play. Selected information on the rackets is given below: Sales in units in the second quarter have been as follows: All sales are made through the company's own retail outlets. The Racket Division has the following quarterly fixed costs: Keeping the sales mix unchanged, which amount is closest to the break-even dollar sales of the Racket Division for April? $185, 093 $86, 377 $567, 033 $582, 623 $480, 907