I was able to easily solve portion A but can someone explain how I would find the answer for portion B. I used the equation =0.2*650+(1-0.2)*280 but the answer was incorrect.

Not all the items in your office supply store are evenly distributed as far as demand is concerned, so you decide to forecast demand to help plan your stock. Past data for legal-sized yellow tablets for the month of August are. Week 1 Week 2 Week 3 Week 4 250 345 545 650 a. Using a three-week moving average, what would you forecast week 5 to be? (Round your answer to the nearest whole number.) Forecast for the week 5 513 b. Using exponential smoothing with a = 0.40, if the exponential forecast for week 3 was estimated as the average of the first two weeks [(250 + 345)/2 = 298], what would you forecast week 5 to be? (Round your interim calculations and answer to the nearest whole number.) Forecast for the week 5