The yearly rainfall (in cm) of a town is given below.
| Year | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
| Rainfall (in cm) | 82 | 90 | 76 | 88 | 94 | 80 | 97 |
The 5-year moving average (in cm) for the year 2022 is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 87
A 5-year moving average is placed against the middle year of its five years. The year 2022 is the middle of the five years 2020 to 2024, so
\( \displaystyle \frac{76 + 88 + 94 + 80 + 97}{5} = \frac{435}{5} = 87 \)
Why the other options are incorrect
Option (1) 86 — Incorrect. It is the mean of 2018 to 2022, which is the 5-year moving average for 2020, not for 2022.
Option (2) 85.6 — Incorrect. It is the mean of 2019 to 2023, which is the 5-year moving average for 2021.
Option (4) 94 — Incorrect. It is the actual rainfall of 2022, not a moving average.