Sheridan Company sells two types of computer hard drives. The sales mix is 30% (Q-Drive) and 70% (Q-Drive Plus). Q-Drive has variable costs per unit of $45 and a selling price of $105. Q-Drive Plus has variable costs per unit of $60 and a selling price of $150. The weighted-average unit contribution margin for Sheridan is

$105.

$69.

$81.

$53.

Guys, please try to explain it a little bit! thanksss