DE22-18 Kay Pak's e-tail poster business incurs $7.000 of fixed expenses and has the fol- lowing sales and variable expenses per poster: Sale price per unit.... Variable expense per unit Regular Large Posters Posters $35 $70 21 40 Suppose Pak estimates she will sell 10 regular posters for every 2 large posters. Compute the weighted-average contribution margin per unit. Carry your computations to five decimal places.