The following table shows the gold prices in recent 4 years: Price Price Index Year (US$ per ounce) (Base 2018) 2018 1328 12018 =? 2019 1294 12019 =? 2020 1562 12020 =? 2021 1949 12021 =? (a) Calculate all the simple price indexes by using 2018 as the base year. (b) Calculate the percentage change from 2020 to 2021. A company has collected and smoothened its historical yearly sales data of a product from 2015 up to 2021. The following table shows the sales and moving average figures. Year Sales ($ thousands) Three-year moving average Five-year moving average 2015 A -- 2016 326.0 324.0 -- 2017 344.0 C 2018 383.0 371.0 E 367.4 2019 B 389.0 F 2020 398.0 D -- 2021 428.0 Calculate the missing values of A, B, C, D, E and F (Correct to 1 decimal place)."