Dollar-Value LIFO

On January 1, 2018, Sato Company adopted the dollar-value LIFO method of inventory costing. Sato's ending inventory records appear as follows:

Year Current Cost Index

2018 $33,700 100

2019 $48,780 120

2020 $50,960 130

2021 $60,480 140

Required: Compute the ending inventory for the years 2018, 2019, 2020, and 2021, using the dollar-value LIFO method.

Year Ending inventory

2018 $33,700

2019 $42,040

2020 $

2021 $

I need help with years 2020 & 2021. I had originally got $38632 for 2020 but it's wrong. Please help & explain how the answer would be found. Thank you :)