The following data sets show the quantities purchased for 3 items over the past 3 years and the prices paid for them: Quantities Item B 2018 800 600 300 2019 700 650 600 2020 500 700 800 Prices Item 2018 30 35 50 2019 31 37 60 2020 32 40 65 Using 2018 as the base year, calculate a Laspeyre's price index for 2020. (4 marks)