As a salesperson at trading cards unlimited justin receives a monthly base pay plus commission on all that he sales. if he sales $400 worth of merchandise in one month je is paid $292 if he sales $900 worth of merchandise in one month he is paid $407. find justins salary when he sales $3200 worth of merchandise

In this item, we will be able to form a system of linear equation which are shown below,
                                  292 = 400x + y
                                  407 = 900x + y
where x is the percent of the commission that he gets and y is the wage. The values of x and y from the equations are 0.23 and 200. This means that Justin earns a fixed wage of 200 per day and a commission which is equal to 23%. 

Substituting the known values to the equation,
                                   S = (0.23)(3200) + 200 = 936.

Therefore, Justin could have earned $936 had he sold $3,200 worth of merchandise. 

Where are the calculations?