Please help with explanation i got stuck

Smith Company can produce two types of carpet cleaners, Brighter and Cleaner. Data on these two products are as follows: Brighter Cleaner Sales volume in units 520 780 $765 $1,300 Unit sales price Unit variable cost 306 585 The number of machine-hours to produce one unit of Brighter is 1 while the number of machine-hours for each unit of Cleaner is 2. Total fixed costs for the manufacture of both products are $248,000. Required: 1. Using a spreadsheet, determine the breakeven point in total units for Smith Company, assuming that the sales mix (based on physical volume) remains constant. (Round "Sales mix (based on units)" and "Weighted average contribution margin/unit" to 2 decimal places. Round your final answer for "Total units to breakeven" up to the nearest whole unit.) Brighter Cleaner 715 459 Contribution margin/unit Sales mix (based on units) 0.40 0.60 1.00 Wtd. avg. cm per unit 612.60 Total fixed costs to be recovered Weighted-average cm/unit Total units to breakeven