Open our practice workbook. Click the Challenge tab in the bottom-left of the workbook. 3 In cell B8, create a function that calculates the average of the sales in B2:B7. 4 The workbook shows Dave's monthly sales amounts for the first half of the year. If he reaches a $200,000 mid-year average, he will receive a 5% bonus. Use Goal Seek to find how much he needs to sell in June in order to make the $200,000 average. 5 When you're finished, your workbook should look like this: B Month Sales 2 January $157,274.00 3 February $187,349.00 4 March $179,291.00 5 April $202,025.00 6 May $212,685.00 7 June $261,376.00 8 Mid-Year Average $200,000.00