The table shows the index number for the cost of coffee, tea, and cocoa, using 2015 as base year (index = 100).
Year | Index number |
---|---|
August 2016 | 101.361 |
August 2018 | 106.608 |
August 2020 | 100.607 |
The price of 100 grams of instant coffee in 2015 was £2.72.
Use the data in the table to estimate the cost of 100 grams of instant coffee in 2018.
A student does the following calculation to reach a conclusion about the cost of coffee, tea, and cocoa.
Year | Index number |
---|---|
August 2016 | 101.361 |
August 2018 | 106.608 |
August 2020 | 100.607 |
106.608 - 101.361 = 5.247 The cost of all coffee, tea, and cocoa increased by 5.247% between August 2016 and August 2018 |
Is the student correct?
Give two reasons for your answer.
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