casper inc. which has fixed costs of $1400000 sells three products whose sales price, variable cost per unit, and percentage of sales units are presented in the table below. sales price product A $16 B $48 C $103 variable cost 8 30 85 sales mix 40% 50% 10% a) what is the weighted average unit contribution margin? b)at the break-even point, how many units of product A must be sold? c) to make a profit of $910000, how many units of product B must be sold