The first answer is correct. The second and third are incorrect.

Problem 3-12 Assume that your stock of sales merchandise is maintained based on the forecast demand. If the distributor's sales personnel call on the first day of each month, compute your forecast sales by each of the three methods requested here. June July August ACTUAL 145 185 215 a. Using a simple three-month moving average, what is the forecast for September? (Round your answer to 2 decimal places.) Forecast for September 181.67 b. Using a weighted moving average, what is the forecast for September with weights of 0.30, 0.40, and 0.30 for June, July, and August, respectively? (Do not round intermediate calculations. Round your answer to 2 decimal places.) Forecast for September 163.50 c. Using single exponential smoothing and assuming that the forecast for June had been 134, forecast sales for September with a smoothing constant a of 0.20. (Round your answer to 2 decimal places.) Forecast for September 170.62