Can someone please help me understand this? I am not sure how i got these wrong.

The Carbondale Hospital is considering the purchase of a new ambulance. The decision will rest partly on the anticipated mileage to be driven next year. The miles driven during the past 5 years are as follows: Year 1 2 3 4 5 Mileage 3,000 3,950 3,400 3,850 3,800 a) Using a 2-year moving average, the forecast for year 6 = 3825 miles (round your response to the nearest whole number). b) If a 2-year moving average is used to make the forecast, the MAD based on this = 141.7 miles (round your response to one decimal place). (Hint: You will have only 3 years of matched data.) c) The forecast for year 6 using a weighted 2-year moving average with weights of 0.40 and 0.60 (the weight of 0.60 is for the most recent period) = 3,820 miles (round your response to the nearest whole number). The MAD for the forecast developed using a weighted 2-year moving average with weights of 0.40 and 0.60 = 176.7 miles (round your response to one decimal place). (Hint: You will have only 3 years of matched data.) d) Using exponential smoothing with a = 0.20 and the forecast for year 1 being 3,000, the forecast for year 6 = 3,444 miles (round your response to the nearest whole number)