Using the spreadsheet, Emma can immediately see how many units she needs to sell to achieve particular operating – income levels, given alternative levels of fixed costs and variable cost per unit that she may face. For example, 32 units must be sold to earn an operating income of $1,200 if fixed costs are $2,000 and variable cost per unit is $ 100. Emma can also use Exhibit 3-4 to determine that she needs to sell 56 unit to break even if fixed cost of the booth rental at the Chicago fair is raised to $2,800 and if the variable cost per unit charged by the test-prep package supplier increases to $150. Emma can use information about costs and sensitivity analysis, together with realistic predictions about how much she can sell to decide if she should rent a booth at the fair.