Can you help me solve C (I don't understand how they got 121.7) and D thank you

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	3,050	4,050	3,450	3,750	3,800

a) Using a 2-year moving average, the forecast for year 6 =

3775 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 =

100 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 0.45 and 0.55 (the weight of 0.55 is for the most recent period) = 3777 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 0.45 and 0.55 =

121.7 miles (round your response to one decimal place). (Hint: You will have only 3 years of matched data.)

d) Using exponential smoothing with = 0.20 and the forecast for year 1 being 3,050, the forecast for year 6 =

__________ miles (round your response to the nearest whole number).