Answer:
(a) "Cost of living" index decrease by 14.42% between 2018 and 2019.
(b) "Cost of living" index increase by 30.73% between 2018 and 2020.
(c) "cost of living" index increase by 45.05% between 2018 and 2020.
Explanation:
Note: See the attached excel file for the calculations of the "cost of living" index for eash of 2018, 2019, and 2020 using 2018 as the base year.
(a) by how much does a "cost of living" index increase between 2018 and 2019.
Cost of living index in 2018 = 100%
Cost of living index in 2019 = 85.68%
Increase (decrease) in cost of living index = Cost of living index in 2019 - Cost of living index in 2018 = 85.68% - 100% = (14.42%)
Therefore, "cost of living" index decrease by 14.42% between 2018 and 2019.
(b) by how much does a "cost of living" index increase between 2018 and 2020.
Cost of living index in 2018 = 100%
Cost of living index in 2020 = 130.73%
Increase (decrease) in cost of living index = Cost of living index in 2020 - Cost of living index in 2018 = 130.73% - 100% = 30.73%
Therefore, "cost of living" index increase by 30.73% between 2018 and 2020.
(c) by how much does a "cost of living" index increase between 2019 and 2020
Cost of living index in 2019 = 85.68%
Cost of living index in 2020 = 130.73%
Increase (decrease) in cost of living index = Cost of living index in 2020 - Cost of living index in 2018 = 130.73% - 85.68% = 45.05%
Therefore, "cost of living" index increase by 45.05% between 2018 and 2020.
