Iam being a company gives each new salesperson a commission of $300 for the sale of a new car. the salesperson will receive a $100 increase for each additional car the person sells that week, so the person gets $400 for the next sale that week. which equation can find the number of car as a salesperson must sell to earn $4200 in a week? recall that a1+d(n-1) is equivalent to an.