a= Answer a= Forecast for week 2= 21 0.5*(21-21)=21 Forecast for week 3= 21 0.5*(23-21)=22 Forecast for week 4= 22 0.5*(27-22)=24.5 Forecast for week 5= 24.5 0.5*(36-24.5)=30.25 Forecast for week 6= 30.25 0.5*(24-30.25)=27.13 Forecast for week 7= 27.13 0.5*(29-27.13)=28.07 Forecast for week 8= 28.07 0.5*(36-28.07)=32.04 Forecast for week 9= 32.04 0.5*(20-32.04)=26.02 Forecast for week 10= 26.02 0.5*(25-26.02)=25.51 Answer b=