7. (15) Simple exponential smoothing method is being used to forecast weekly car sales at Fairfax Toyota. Suppose the demand is initially estimated to be 20 cars per week. We have obtained two data points: 10 cars were sold during last week, and 30 cars are sold during the current week. Assume =0.5. After observing the sales in these two weeks, please forecast the number of cars to be sold for next week. For simplicity, assume the number of cars can be a continuous number