Answer:
The inflation rate is different using the two methods as the rate of inflation calculated by the CPI holds basket of goods and services constant while the GDP deflator allows it to change.
Explanation:
i. Value of market basket of the good in 2020 = ($50*2) + ($5*6) = $130
Value of market basket of the good in 2021 = ($70*2) + ($6*6) = $176
CPI in 2020 = ($130 / $130) * 100 = 100
CPI in 2021 = ($176 / $130) * 100 = 135.38
Thus, The percentage change in overall price level is = [(135.38 - 100) / 100) * 100 = 35.38%
ii. Nominal GDP in 2020 = ($50 * 20) + ($5 * 60) = $1300
Nominal GDP in 2021 = ($70 * 21) + ($6 * 80) = $1950
Real GDP in 2020 = ($50 * 20) + ($5 * 60) = $1300
Real GDP in 2021 = ($50 * 21) + ($5 * 80) = $1450
GDP deflator in 2020 = (Nominal GDP in 2107 / Nominal GDP in 2107) * 100 = ($1300 / $1300) * 100 = 100
GDP deflator in 2021 = (Nominal GDP in 2108 / Nominal GDP in 2108) * 100 = ($1950 / $1450) * 100 = 134.48
Thus, the percentage change in overall price level is = [(134.48 - 100) / 100) * 100 = 34.48%