Answer:
Real GDP for Tyrovia for 2018 using 2009 base prices = (90 x $5) + (60 x $4) = $450 + $240 = $690
Nominal GDP for Tyrovia for 2018 = (90 x $6) + (60 x $10) = $540 + $600 = $1,140
2018 CPI for Tyrovia = [($6/$5) + ($10/$4)] / 2 = (1.2 + 2.5) / 2 = 3.7 / 2 = 1.85 x 100 = 185