Directions:
Directions for the following 4 questions: The table below shows the sales (in thousands of units) of four products P, Q, R and S of a company over three years. Study the table and answer the questions that follow.
Year | P | Q | R | S
2021 | 20 | 30 | 25 | 15
2022 | 25 | 35 | 20 | 20
2023 | 30 | 40 | 30 | 25
What was the total number of units (in thousands) of all four products sold in 2022?