Rusty co. sells two products, x and y. last year, rusty sold 5,000 units of x and 35,000 units of y. related data are: unit selling unit variable unit contribution product price cost margin x $110.00 $70.00 $40.00 y 70.00 50.00 20.00 what was rusty co.'s sales mix last year? a. 60% x, 40% y b. 30% x, 70% y c. 12.5% x, 87.5% y d. 58% x, 42% y