Ejercicio $2$: An$$lisis de Costo$-$Volumena$)$ L$$pez Plumbing reported the following:Revenues $$4,500$Variable manufacturing costs $ $900$Variable nonmanufacturing costs $ $810$Fixed manufacturing costs $ $630$Fixed nonmanufacturing costs $ $545$Required:a$.$ Compute contribution margin.b$.$ Compute contribution margin percentage.c$.$ Compute gross margin.d$.$ Compute gross margin percentage.e$.$ Compute operating income.b$)$ Furniture, Inc., sells lamps for $$30.$ The unit variable cost per lamp is $$22.$ Fixedcosts total $$9,600.$Required:a$.$ What is the contribution margin per lamp?b$.$ What is the breakeven point in lamps?c$.$ How many lamps must be sold to earn a pretax income of $$8,000?$d$.$ What is the margin of safety, assuming $1,500$ lamps are sold