What is the cumulative effect of the inventory error on total gross profit for the 2 years?

Smart Watch Company reported the following income statement data for a 2-year period.
2019 2020
Sales revenue $220,000 $250,000
Cost of goods sold
Beginning inventory 32,000 44,000
Cost of goods purchased 173,000 202,000
Cost of goods available for sale 205,000 246,000
Ending inventory 44,000 52,000
Cost of goods sold 161,000 194,000
Gross profit $ 59,000 $ 56,000
Smart uses a periodic inventory system. The inventories at January 1, 2019, and December 31, 2020, are
correct. However, the ending inventory at December 31, 2019, was overstated $6,000.
Instructions
a. Prepare correct income statement data for the 2 years.
b. What is the cumulative effect of the inventory error on total gross profit for the 2 years?
c. Explain in a letter to the president of Smart Watch Company what has happened, i.e., the nature of
the error and its effect on the financial statements.