*please show how to work this out with details thank you. I know i have the answer but i don't understand how they got this.

9. The Horner Company makes three products. The cost dat lr these three produets is follows: Product AProduct B Product C S40 $10 4 Selling price Direct Material Cost Direct Labor Cost Other Variable Costs S20 2.50 1.50 Total annual fixed manufacturing costs are $440,000 and the annual fixed non- manufacturing costs are $400,000. The firm's experience has been that about 20 percent of dollar sales come from product A, 60 percent from B, and 20 percent from C. Determine the number of units of Product B to be sold at the break-even point. Salo 20 620 840,000 Sale 20 O,oOD 2 Lu 0,0006 -60, suo